Number of half-lives is 3
The decay of this radioactive unknown compound is a first-order process.
We can express the time dependence of its mass m using a first-order integrated rate law, where k is the rate constant:
mt = mass at time t
m0 = initial mass
t = time
Procedure:
1) We need to find "k":
From the first-order rate law we clear k,
[tex]\frac{mt}{mo} = e^{-kxt}[/tex]
㏑[tex](\frac{mt}{mo})= -kxt[/tex]
[tex]\frac{ln(\frac{mt}{mo}) }{-t} = k[/tex]
[tex]k=\frac{ln(\frac{65.59ng}{ 524.7 ng} )}{-47 }[/tex]
k = 0.044[tex]days^{-1}[/tex]
2) We find the half-life from the value of k we have just calculated:
[tex]t\frac{1}{2}[/tex] =[tex]\frac{ln2}{k}[/tex] = 15.7days
3) The number of half-lives of the unknown sample is:
Number of Half-lives = 47 days / 15.7 days = 3 (approx.)
Hence 3 is a correct answer.
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If the chromium, Cr, contamination in water is 5ppm, how many grams of Cr are present in 1000g of pond water?
5 ppm of Cr means 5 mg is present in 1 L of water. Then, 1000 g of water is containing 5 mg or 0.005 g of chromium.
What is ppm ?PPM or part per million is a term used to express the concentration of a solution. 1 ppm is equal to 1 mg of the solute in 1000 ml or in 1 L of the solution.
ppm = weight of solute/mass of solution ×10⁶. = mg/L
ppm is used to express very minute quantity of ay sample. Usually used in the concentration of heavy metals in water.
It is given that the concentration of Cr in water is 5 ppm, which means 5 mg per one liter of water. 1 l of water is 1000 ml or 1000 g of water. Hence, 1000 g of water contains 5 mg or 0.005 g of Cr.
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which of these variables are not state functions? which of these variables are not state functions? m (mass) u (internal energy) q (heat) t (temperature) w (work) v (volume)
The variables that are not state functions are m (mass), q (heat), and w (work).
What is work?Work is an activity that requires physical or mental effort and is done in exchange for money or other rewards. It can also be seen as an exchange of energy, where an individual puts in effort in order to achieve a desired outcome. Work can be done in a variety of fields and can range from manual labor to professional jobs. It is an important part of many people's lives and can be a source of fulfillment and satisfaction, as well as providing a means of economic security. Work can also be a source of stress, but when done properly can be a great way to make a living, develop skills, and better oneself.
Therefore, The variables that are not state functions are m (mass), q (heat), and w (work).
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carbohydrates serve as a vital source of chemical energy to the human body. carbohydrates are broken down into smaller units of glucose, among other sugars, providing energy to various muscles and orgnas, including the brain. on average, for every 15.0g of carbohydrates consumed, the body will store 250kj of energy.convert this energy value to kilocalories (kcal).
The energy value to kilocalories (kcal) would be 32.5 kcal.
What is the difference between energy value and kilocalories?One kilogram of water requires one kilocalorie (1 kcal, or 1000 calories) of heat energy to raise its temperature by one degree Celsius (°C). Joule is the SI-standard unit for energy (J). About 4.18 calories make up one kcal.
The phrase used to describe how much energy is needed to raise a liter of water's temperature by one degree Celsius at sea level. The term "calorie" is frequently used in nutrition terminology to describe a unit of dietary energy.
Let the equation be
1 kJ = 1,000 J
1 cal = 4.184 J
1 kcal = 1,000 cal
136 kj x 1000j/1kj = 1.36 x [tex]$$10^5[/tex] J
simplifying the equation, we get
1.36 x [tex]$$10^5[/tex] J x 1 cal/4.184J = 32, 500
32500 cal x 1 kcal/1,000 cal = 32.5 kcal.
Therefore, the energy value to kilocalories (kcal) would be 32.5 kcal.
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How many oxygen formula units are in 85 grams are in (insert pic formula)? MM=601.93
50 POINTS!!!!!!!!
There are 6.7 * 10^23 oxygen atoms
What is the mole?The mole is a unit of measurement in chemistry used to express amounts of a chemical substance. One mole is defined as the amount of a substance that contains Avogadro's number of entities, which is approximately 6.022 x 10^23 entities
The first step is to get the number of moles of the compound.
Number of moles =85 grams/602 g/mol
= 0.14 moles
Then we have the number of oxygen atoms as;
0.14 moles * 8 * 6.02 * 10^23
= 6.7 * 10^23 oxygen atoms
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For NH4NO3(s) write a balanced equation. Add type of reaction and oxidation charges for each element if applicable.
In a redox reaction, there is a transfer of electrons
What is a balanced redox reaction?The question is incomplete but it seems to have something to do with redox reactions.
A balanced redox reaction is a chemical equation that represents a redox (reduction-oxidation) reaction with the same number of atoms of each element on both the reactant and product sides and the same total charge on both sides. In a redox reaction, there is a transfer of electrons from one substance (the reducing agent) to another substance (the oxidizing agent).
In order to balance a redox reaction, you need to balance the number of atoms of each element in the reaction, and also balance the charges.
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What is the mass in grams of 7.55x10^23 atoms of nitrogen?
N(14.01). Round off answer (at end of calculation) to 3 significant figures or it will be counted wrong.
Do not include unit, g.
Based on the mass of 1 mole of nitrogen atoms, 7.55 x 10²³ atoms of nitrogen have a mass of 17.56 grams.
What is the number of atoms in 1 mole of nitrogen?The number of atoms in 1 mole of nitrogen = 6.02 * 10²³ atoms
The mass of 1 mole of atoms of nitrogen = 14 g
Hence, 6.02 * 10²³ atoms has a mass of 14.01 g
Mass of 7.55 x 10²³ atoms = 14.01 g/mol * 7.55 x 10²³ / 6.02 * 10²³
The mass of 7.55 x 10²³ = 17.56 g
So,7.55 x 10²³ atoms of nitrogen have a mass of 17.56 grams.
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make the structure of pamitoleic acid. show your photo below with a lasso around the double bond structure in the carbon chain.
The chemical formula of pamitoleic acid is CH₃(CH₂)5CH=CH(CH₂)₇COOH. The structure of pamitoleic acid is given in the image attached below.
Palmitoleic acid has been known to have a lot of beneficial effects on insulin sensitivity, cholesterol metabolism, and hemostasis. It has been concluded that palmitoleic acid may prevent beta-cell apoptosis induced by glucose or saturated fatty acids.
Recently, studies have reported that palmitoleic acid is useful in treating disorders related to skin hyperpigmentation, fibrosis and as an adjuvant in formulations for the treatment of secondary infections caused by gram-positive bacteria.
Palmitoleic acid is one of the most common acids which is found in omega-7 fatty acids.
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A saturated aqueous solution of CdF2 is prepared. The equilibrium in the solution is represented above. In the solution, [Cd2+]eq=0.0585M and [F−]eq=0.117M. Some 0.90MNaF is added to the saturated solution. Which of the following identifies the molar solubility of CdF2 in pure water and explains the effect that the addition of NaF has on this solubility?
CdF2(s)⇄Cd2+(aq)+2F−(aq)
The molar solubility of CdF₂ in pure water is 0.0585M, and adding NaF decreases this solubility because the equilibrium shifts to favor the precipitation of some CdF₂. The correct option is A.
According to the statement, the option that identifies the molar solubility of CdF₂ in pure water and explains the effect that the addition of NaF has on this solubility is [CdF₂]eq = [Cd₂+]eq = 0.0585 M (since the solubility product expression for CdF₂ gives Ksp = [Cd₂+][F-]², and F- is in excess).
The molar solubility of CdF₂ in pure water can be determined by calculating the concentration of Cd₂+ and F− ions in the saturated solution, and then using the stoichiometry of the equilibrium reaction to determine the concentration of CdF₂ that would dissolve in pure water.
From the equilibrium equation: CdF₂(s) ⇄ Cd₂+(aq) + 2F−(aq), we know that for every mole of CdF₂ that dissolves, 1 mole of Cd₂+ and 2 moles of F− ions are produced.
The effect of adding NaF to the saturated solution can be explained by the common ion effect. When NaF is added, it provides additional F− ions, which are already present in the saturated solution, and thus increases the concentration of the common ion.
This leads to a shift in the equilibrium to the left, causing more CdF₂ to precipitate out of solution until a new equilibrium is established. As a result, the molar solubility of CdF₂ in the solution decreases.
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Complete question:
CdF₂(s)⇄Cd₂+(aq)+2F−(aq) A saturated aqueous solution of CdF₂ is prepared. The equilibrium in the solution is represented above. In the solution, [Cd₂+]eq=0.0585M and [F−]eq=0.117M. Some 0.90MNaF is added to the saturated solution. Which of the following identifies the molar solubility of CdF₂ in pure water and explains the effect that the addition of NaF has on this solubility?
a. The molar solubility of CdF₂ in pure water is 0.0585M, and adding NaF decreases this solubility because the equilibrium shifts to favor the precipitation of some CdF₂.
b. The molar solubility of CdF₂ in pure water is 0.0585M, and adding NaF has no effect on the solubility because only changes in temperature can increase or decrease the molar solubility of an ionic solid.
c.The molar solubility of CdF₂ in pure water is 0.117M, and adding NaF decreases this solubility because the equilibrium shifts to favor the precipitation of some CdF₂.
d. The molar solubility of CdF₂ in pure water is 0.176M, and adding NaF increases this solubility because the Na+ ions displace the Cd₂+ ions, causing the equilibrium to shift to favor the products.
draw and name the product for the reaction between an alkyne and one equivalent of hcl . 3 methyl 1 butyne or 3 methyl but 1 yne is a 4 carbon chain with a triple bond between carbons 1 and 2 and a methyl substituent on carbon 3. this reacts with h c l to give the product.
the outcome of combining an alkyne with one equivalent of hcl is st -CEC-H + 1H-CI. 3-methyl-1-butyne 2-chloro-3-methyl-1-butene.
An alkyne is a type of hydrocarbon with a triple bond between two carbon atoms, which makes it unsaturated and more reactive than its corresponding alkane or alkene. Alkynes have the general formula CnH2n-2 and can have multiple triple bonds, giving rise to a range of isomers with different properties. Alkynes are used in many industrial processes, such as in the production of polymers, solvents, and pharmaceuticals, and are also important intermediates in organic synthesis. Alkynes can undergo various types of reactions, such as addition, substitution, and polymerization, and their reactivity can be modulated by the choice of substituents, reaction conditions, and catalysts. Alkynes are also of interest in the field of materials science, as they can form strong covalent bonds with metals and semiconductors, and can be used as building blocks for molecular electronics and nanotechnology.
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chem lab explain the resulting shift in equilibrium and any reaction that occurs to explain the change in color observed.
A chemical system is defined as a system at which equilibrium can be temporarily shifted out of equilibrium by adding or removing one or more of the reactants or products.
Le Chatelier`s Principle states that, "when a system at equilibrium is subjected to a change in temperatures, pressure, or concentration of a reactant or product, the system will, if possible shift its equilibrium position so as to partially counteract the effect of the change".
In equilibrium shifting, if the system gets darker red in color, then the equilibrium must be shifting to the right (i.e., towards producing more of the colored product). If the color of the system gets fainter (i.e., or disappears altogether), then the equilibrium must be shifting towards the left (toward the colorless components).
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Use the relative electronegativity values of the elements in formaldehyde to explain why the distribution of electron density appears as it does.
Formaldehyde is a molecule with the chemical formula CH2O. It consists of a central carbon atom bonded to two hydrogen atoms and an oxygen atom, with a double bond between the carbon and oxygen atoms. The relative electronegativity values of the elements involved in formaldehyde are as follows:
• Carbon: 2.55
• Hydrogen: 2.20
• Oxygen: 3.44
What is the role of electronegativity?Electronegativity is a measure of an atom's ability to attract the electrons towards itself in a covalent bond. In a covalent bond between two different atoms, the electrons are shared between them, but they may not be shared equally. In formaldehyde, the oxygen atom is more electronegative than the carbon atom. Therefore, the oxygen atom attracts the shared electrons in the double bond more strongly towards itself, resulting in a greater electron density around the oxygen atom. This creates a partial negative charge on the oxygen atom and a partial positive charge on the carbon atom. Similarly, the hydrogen atoms in formaldehyde have a lower electronegativity than the carbon atom. Therefore, the electrons in the C-H bonds are shared unequally, with a partial negative charge on the hydrogen atoms and a partial positive charge on the carbon atom.
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Which of the following is a heteropolysaccharide? A) amylopectin
B) cellulose
C) pectin
D) chitin
E) none of the above
C): Pectin is a heteropolysaccharide.
Pectin is a heteropolysaccharide, which is a complex carbohydrate made up of different types of monosaccharides. It is commonly found in the cell walls of plants and is used as a gelling agent in the food industry. Amylopectin and cellulose are both homopolysaccharides, meaning they are made up of only one type of monosaccharide (glucose). Chitin is a polymer of N-acetylglucosamine, which is a type of amino sugar, but it is not classified as a heteropolysaccharide.
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cjhegg q12: which region of earth generally has the highest concentration of water vapor and which region generally has the lowest concentration? q13: why would the distribution of water vapor change across the globe in the way that you identified in q13? (i.e., why would the region that had the highest concentration be expected to have the highest concentration and why would the region that had the lowest concentration be expected to have lowest concentration?) q14: how would you describe the movement of the area with the most water vapor over the course of a year? q15: how does the movement you just described relate to what you learned in the solar radiation
The tropical regions of earth contains the highest concentration of water vapor and higher altitudes and poles have the lower water vapor concentration.
What is differential distribution of water vapor ?Lower atmospheric water vapor molecules absorb heat generated from the Earth's surface. In turn, the water vapor molecules emit heat in all directions. The Earth's surface receives some of the heat back.
In the tropics, as the seasons change, a band of extremely humid air sways both north and south of the equator. The Intertropical Convergence Zone, where the easterly trade winds from either hemisphere meet and create almost daily thunderstorms and clouds, includes this ring of dampness.
Water vapor concentrations are higher farther from the equator in the summer-experienced hemisphere and lower in the winter-experienced one.
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define the terms acid and base. also, define ph and describe the relationship between ph and the h concentration of a solution.
Acid is sour taste, corrosive and has lots of H+, while base is soapy and has lots of OH-. A pH is degree to measures how acid or base a solution is. The more H+ ions, the more acidic it is and the lower the pH will be.
Acids and basesThe terms acid and base describe chemical characteristics of the substances. The properties of acids are as follow :
Acid has corrosive traitsAcid has sour tasteAcid turn the litmus from blue to redAcid produces hydrogen (H+) ions when it is added to waterFor example : lemon, vinegar and others
While base (alkalies) has these properties :
Base is soapy or feel slippery to touchBase change the litmus from red to blueBase split to form hydroxide ions or OH- as added to waterFor example : soap and many more
To measure the strength of the acids and bases, we can see from the pH scale. pH stands for potential or power of hydrogen. The pH scale is range from 0 to 14. Acids have a pH below 7, bases have a pH above 7 while pH 7 is said to be neutral.
Thus, the more H+ ions, the more acidic it is and the lower the pH will be.
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The electron is moving from
energy level 2 to energy
level 1 (the ground state).
What happens during this
transition?
A. The electron falls into the nucleus.
B. The electron creates an absorption line (black line) on
a spectrum.
C. The electron emits a photon of EMR.
D. The electron absorbs a photon of electromagnetic
radiation (EMR).
The electron is moving from energy level 2 to energy level 1 the ground state then the electron emits a photon of EMR. Therefore, option C is correct.
What is energy level ?The set distances from an atom's nucleus where electrons may be found are referred to as energy levels. In an atom, the small, negatively charged electrons orbit the central, positively charged nucleus.
The energy of the electron drops when it changes levels, and the atom releases photons. The emission of the photon occurs as the electron transitions from a higher to a lower energy state.
Thus, option C is correct.
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if q > keq, what does that say about the relationship of the system to equilibrium? group of answer choices A. the system is not at equilibrium and will produce more reactants to reach equilibrium (shift to the left). B. the system is at equilibrium. C. the system is not at equilibrium and will produce more products to reach equilibrium (shift to the right). D. there is no relationship between q and keq.
If q > Keq, it means that the reaction quotient, q, has a higher numerical value than the equilibrium constant, Keq and the system is not at equilibrium and will produce more reactants to reach equilibrium (shift to the left).
Therefore, the system is not at equilibrium and will shift in the direction that reduces the value of q and increases the value of Keq, which is toward the side of the reaction with fewer products and more reactants.
In this case, the system will shift to the left (produce more reactants) to reach equilibrium. This suggests that there is an excess of products or a deficiency of reactants in the system compared to what would be present at equilibrium.
Hence the correct option is A.
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The observed lines in the emission spectrum of atomic hydrogen are given by v~(cm−1)=RH(cm−1)(1n21−1n2)cm−1,n>n1 In the notation favored by spectroscopists, v~=1/λ=E/hc and RH=109,677 cm−1. The Lyman, Balmer, and Paschen series refers to n1 =1, 2, and 3, respectively, for emission from atomic hydrogen. Part A What is the highest value of v~ for the Lyman series? Express your answer using six significant figures. What is the highest value of v~ for the Balmer series? Express your answer using six significant figures. What is the highest value of v~ for the Paschen series? Express your answer using six significant figures. What is the highest value of E for the Lyman series? What is the highest value of E for the Balmer series?What is the highest value of E for the Balmer series?What is the highest value of E for the Paschen series?
The formula given relates the frequency of the photon emitted to the difference in energy levels of the hydrogen atom. The energy of the photon is given by
E = hν
where h is Planck's constant and ν is the frequency.
Part A:
The highest value of v~ for the Lyman series corresponds to the transition from n=2 to n=1. Plugging in the values, we get:v~ = RH(1/12 - 1/22) = 3.28984 x 1015 cm-1
The highest value of v~ for the Balmer series corresponds to the transition from n=3 to n=2. Plugging in the values, we get:v~ = RH(1/22 - 1/32) = 1.09737 x 1015 cm-1
The highest value of v~ for the Paschen series corresponds to the transition from n=4 to n=3. Plugging in the values, we get:v~ = RH(1/32 - 1/42) = 4.34013 x 1014 cm-1
To find the highest value of energy (E) for each series, we can use the relationship E = hν. Using Planck's constant (h) and the highest frequency (v~) for each series, we get:
For the Lyman series: E = hv~ = (6.626 x 10-34 J s)(3.28984 x 1015 s-1) = 2.18 x 10-18 JFor the Balmer series: E = hv~ = (6.626 x 10-34 J s)(1.09737 x 1015 s-1) = 6.626 x 10-19 JFor the Paschen series: E = hv~ = (6.626 x 10-34 J s)(4.34013 x 1014 s-1) = 2.76 x 10-19 JHence, the answer is,
The highest value of v~ for the Lyman series corresponds to the transition from n=2 to n=1. Plugging in the values, we get:v~ = RH(1/12 - 1/22) = 3.28984 x 1015 cm-1
The highest value of v~ for the Balmer series corresponds to the transition from n=3 to n=2. Plugging in the values, we get:v~ = RH(1/22 - 1/32) = 1.09737 x 1015 cm-1
The highest value of v~ for the Paschen series corresponds to the transition from n=4 to n=3. Plugging in the values, we get:v~ = RH(1/32 - 1/42) = 4.34013 x 1014 cm-1
Write a short note on the hydrogen spectrum.
The hydrogen spectrum refers to the pattern of lines that are observed when the emission spectrum of hydrogen is analyzed. It is caused by the excitation of electrons in hydrogen atoms, which emit light of specific frequencies as they return to lower energy states. The hydrogen spectrum consists of several series of lines, including the Lyman, Balmer, and Paschen series, which correspond to different electron transitions. The study of the hydrogen spectrum played a crucial role in the development of quantum mechanics and our understanding of atomic structure.
To find the highest value of energy (E) for each series, we can use the relationship E = hν. Using Planck's constant (h) and the highest frequency (v~) for each series, we get:
For the Lyman series: E = hv~ = (6.626 x 10-34 J s)(3.28984 x 1015 s-1) = 2.18 x 10-18 JFor the Balmer series: E = hv~ = (6.626 x 10-34 J s)(1.09737 x 1015 s-1) = 6.626 x 10-19 JFor the Paschen series: E = hv~ = (6.626 x 10-34 J s)(4.34013 x 1014 s-1) = 2.76 x 10-19 JTo learn more about hydrogen spectrum, follow the link:
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calculate the number of moles in 2.3gram of sodium (Na=23).
The number of moles in 2.3 grams of sodium atom is 0.1 moles and is calculated by formula, mass/molar mass.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.It is given as,mass/molar mass= 2.3/23=0.1 moles
Thus, there are 0.1 moles in 2.3 grams of sodium.
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Calculate the pH for each of the cases in the titration of 35.0 mL of 0.190 M KOH(aq) with 0.190 M HI(aq). Note: Enter your answers with two decimal places. before addition of any HI: after addition of 13.5 mL HI: after addition of 20.5 mL HI: after addition of 35.0 mL HI: after addition of 40.5 mL HI: after addition of 50.0 mL HI:
The pH is determined by the relative amounts of acid and base in each circumstance.
What is meant by proportional concentration?The rate of reaction increases with an increase in reactant concentration and decreases with a reduction in reactant concentration. The concentration of reactants has a direct relationship with the rate of reaction. Effect of concentration: According to the law of mass action, the rate of a reaction is directly proportional to the concentration of the reactants, meaning that the rate of a reaction rises as the concentration of the reactants rises. Pressure: Pressure has the ability to raise reactant concentration.The rate is proportional to the reactant's concentration. The rate doubles with a doubling of concentration. The square of a reactant's concentration determines the rate. The rate increases four times when you twice the concentration.a) Before addition of HBr;
Number of moles of C5H5N = 25/1000 L × 0.180 M = 0.0045 moles
pOH = -log[0.0045 M]
pOH = 2.35
pH = 14 - 2.35 = 11.65
b) After addition of 12.5 mL of HBr;
Since the reaction is 1:1
Number of moles of HBr = 12.5/1000 L × 0.180 M = 0.00225 moles
The HBr is the limiting reactant
Amount of excess acid = 0.0045 M - 0.00225 = 0.00225 moles
Total volume of solution = 25mL + 12.5 mL = 37.5mL or 0.0375 L
molarity of excess H+ = 0.00225 moles / 0.0375 L = 0.06 M
pH = - log[0.06 M]
pH = 1.22
c) After addition of 24.0 mL of HBr;
Number of moles of acid = 24/1000 × 0.180 M = 0.00432 moles
Number of moles of excess acid = 0.0045 moles - 0.00432 moles = 0.00018 moles
Total volume of solution = 24.0 mL + 25.0 mL = 49mL or 0.049 L
Molarity of excess acid = 0.00018 moles/ 0.049 L = 0.00367 M
pH = -log[0.00367 M] = 2.4
d) After addition of 25.0 mL of HBr
Number of moles of acid = 25/1000 × 0.180 M = 0.0045 moles
We have an equal number of acid and base hence pH = 11.65
e) After addition of 34.0 mL of HBr;
Number of moles of acid = 34/1000 × 0.180 M =0.00612 moles
We can see that the base is the limiting reactant.
Number of moles of excess base = 0.00162 moles
Total volume of solution = 34 mL + 25 mL = 59mL or 0.059 L
Molarity of excess base = 0.00162 moles/0.059 L = 0.027 M
pOH = -log[ 0.027 M]
pOH = 1.56
pH = 14 - 1.56 = 12.44
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The process of separating Na+ and Cl- against coulomb attractive force is ___________.
A. exothermic
B. Not enough information
C. endothermic
An ionic compound comprised of Na+ and Cl is sodium chloride. An anion is a negative charges chlorine ion (Cl) and a cation is a positive sodium ion (Na+).
What interactions between Cl and Na ions are there?The sodium and chlorine ions exert an electric pull on one another when one sodium electron is transferred to a chlorine ion, binding the sodium and chlorine molecules together.
What kind of force is attractive?Because it attracts objects to itself from any distance, gravitational force is a very well-known example of attraction. More details regarding how this force operates are provided by Newton's global law of gravity.
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What is cellular respiration?
Help pls !!!
Explain how the mass of carbon is conserved during cellular respiration.
Which of the following was Robert A. Millikan able to determine, either from his own work, or by building on the work of J.J. Thomson? Select all that apply. Select all that apply: 0 The existence of an electron The charge of an electron The mass of an electron The model of an atom with a small, positively charged nucleus.
Robert A. Millikan able to determine, either from his own work, The mass of an electron. Hence, the correct option is (c).
Robert A. Millikan was able to determine the charge of an electron, but the discovery of the electron itself was made by J.J. Thomson. Millikan's work built on Thomson's discovery and helped to refine our understanding of the properties of electrons. By conducting the oil drop experiment, Millikan was able to measure the charge of an electron with great precision. He observed the motion of tiny oil droplets that were suspended in an electric field, and by measuring the strength of the electric field and the speed of the droplets, he was able to calculate the charge of each droplet. By adjusting the strength of the electric field, he was able to find the smallest possible charge that a droplet could have, which corresponded to the charge of a single electron. However, Millikan did not determine the mass of an electron, as this was already known from Thomson's work on the charge-to-mass ratio of electrons. Additionally, Millikan did not propose a model of an atom with a small, positively charged nucleus, as this idea was developed later by Ernest Rutherford.
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he two reactions above, show routes for conversion of an alkene into an oxirane. if the starting alkene is cis-2-butene the configurations of the oxirane products, a and b are product a: cis product b: trans will either of these two oxirane products rotate the plane of polarization of plane polarized light? yes are you sure? an error was detected in your answer. check for typos, miscalculations, etc. before you submit this item again. submit answer try another version 10 item attempts remaining
Separation into two diametrically opposed social, political, or religious movements.
What is meant by polarization?Polarization, a property of transverse waves, describes the geometric orientation of the oscillations The direction of the oscillation in a transverse wave is the opposite of the wave's motion direction. A simple example of a polarised transverse wave is vibrations along a taut string, as a guitar string. Depending on how the string is pulled, the vibrations can be horizontal, vertical, or at any angle perpendicular to the string. Since the displacement of the oscillating particles always occurs in the direction of the wave's propagation, polarisation does not occur in longitudinal waves, such as sound waves in a liquid or gas.
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predict the major product for each of the following reactions:5-methyl-3-hexyne or 5-methylhex-3-yne is a 6 carbon chain with a triple bond between carbons 3 and 4 and a methyl substituent on carbon 5. this reacts with c l 2 to give product 1. product 1 then reacts with c l 2 to give product 2.
When 5-methyl-3-hexyne (or 5-methylhex-3-yne) reacts with Cl2, the triple bond will be broken, and two Cl atoms will be added to the two adjacent carbons, forming a dihalogenated alkene.
This will result in the formation of a trans-dihalogenated alkene, where the two Cl atoms are on opposite sides of the double bond. The major product for the first reaction will be 5-methyl-3-hexene-1,2-dichloro, which is formed by the addition of two Cl atoms to the carbons 3 and 4, and the formation of a double bond between carbons 2 and 5. The major product of this reaction will be 5-methyl-3,4-dichloro-2-hexene, which is formed by the addition of two Cl atoms to the carbons 2 and 5, and the addition of two more Cl atoms to the carbons 3 and 4.
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. Why do you need to fill the bomb with pure oxygen? What would happen if you skipped that step and just allowed the bomb to fill with air?
To calculate the heating value of both solid and liquid fuels, one uses a bomb calorimeter. It is made up of a powerful steel shell called a bomb. It is composed of a base that holds the platinum cross.
What exactly is a solid defined as?
It seems evident what a solid is; a solid is typically thought of as hard and firm. However, closer examination makes the term less clear. For instance, a butter cube is unmistakably a solid since it becomes hard after being kept in a refrigerator. Having stayed on the
A crystalline solid is what?
A solid that has its component atoms and molecules (or occasionally ions) arranged in a crystalline structure microscopic structure is referred to as a crystal lattice (also referred as a crystal). A homogeneous microscopic structure known as a crystal lattice extends across every point of the crystalline solid.
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find the mass of a 50.0 ml quantity of water if the density of water is 100 grams/ml
Answer: 5 × 10^3 g
Or, without significant figures, 5000 g.
To find the mass when given volume and density, multiply the volume with density.
Dimensional analysisWe can solve using dimensional analysis or the 'cancelling out units' method.
We are looking for the mass, which will be in grams (g).Write volume and density as fractions so that other units cancel.[tex]m = \frac{50.0\ mL}{1}*\frac{100\ g}{1\ mL}[/tex]
[tex]m = \frac{50.0}{1}*\frac{100\ g}{1}[/tex] Since mL is in the top and bottom, they cancel out.
[tex]m = 5000\ g[/tex] Multiply to find the answer.
[tex]m = 5 * 10^{3}\ g[/tex] Write the answer with significant figures.
Therefore, the mass of 50.0 mL of water is 5 × 10^3 g.
This is the same as 5000 g if we do not consider significant figures.
Significant figuresIf we use significant figures in this answer, we only keep 1 significant figure. When multiplying numbers, the final answer will have the same amount of significant figures as the numbers in the question with the least amount of significant figures.
If the numbers in the question have different amounts of significant figures, we will take the least amount of significant figures from the problem.
We had two numbers from the problem and they had different amounts of significant figures:
50.0—This has 3 significant figures.100—This has 1 significant figure. This number has the least amount of significant figures.So, our final answer should only have 1 significant figure.
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10. Changing the volume of the system alters the equilibrium position of this equilibrium:
2( ) 2( ) 3( ) 3 2 N H NH gg g
+
But a similar change has no effect on this equilibrium:
2( ) 2( ) ( ) 2 H Cl HCl gg g
+
Explain.
a. Using proper arrow formalism, write down a mechanism for the formation of the acylium ion from the reaction between acetyl chloride and aluminium chloride. b. As a model system and using proper arrow formalism, write a mechanism for the Friedel-Crafts acylation of bromobenzene using the acylium ion formed in (a). To simplify your work, write a mechanism in which carbon-2 of bromobenzene (ortho- position) is the nucleophilic atom.
The mechanism of the reactions of both the subparts of the questions is below:
A)The formation of the acylium ion from the reaction between acetyl chloride and aluminium chloride can be described by the following mechanism:
Step 1: Formation of the complex
AcCl + AlCl3 → [AcCl-AlCl3]
Step 2: Deprotonation to form the acylium ion
[AcCl-AlCl3] → Ac+ + AlCl4-
In step 1, the acetyl chloride molecule reacts with aluminium chloride to form a complex. In step 2, the complex undergoes deprotonation to form the acylium ion, which is stabilized by the aluminium chloride.
(b) The mechanism for the Friedel-Crafts acylation of bromobenzene using the acylium ion formed in (a) can be described by the following steps:
Step 1: Formation of the complex
Ac+ + AlCl4- → [Ac-AlCl4]
Step 2: Attack of the ortho-carbon of bromobenzene
C6H5Br + [Ac-AlCl4] → C6H4Br-2-COCH3 + AlCl3
Step 3: Regeneration of the catalyst
AlCl3 + [Ac-AlCl4] → AcCl + AlCl4-
In step 1, the acylium ion formed in (a) reacts with aluminium chloride to form a complex. In step 2, the complex reacts with bromobenzene, and the ortho-carbon attacks the carbonyl carbon of the acylium ion to form a new carbon-carbon bond. In step 3, the catalyst is regenerated, and acetyl chloride is produced as a byproduct.
The arrow formalism for the three steps can be written as follows:
Step 1:
Ac+ AlCl4- [Ac-AlCl4]
↑ ↓ ↑
Step 2:
C6H5Br [Ac-AlCl4] C6H4Br-2-COCH3 AlCl3
↑ ↓ ↑ ↑
Nucleophile Electrophile Product Catalyst
Step 3:
AlCl3 [Ac-AlCl4] AcCl AlCl4-
↑ ↓ ↑ ↓
Catalyst Complex Byproduct Catalyst
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TASK 2 - Pass 2B.P4 Identify an alkene and carboxylic acid using primary observations. To achieve 2B.P4, learners should follow guidance to identify an alkene and a carboxylic acid (for example, ethanoic acid) from primary observations. Learners will be expected to identify an alkene in the way described in 1B.4. For ethanoic acid this is by its pH and its reaction with sodium carbonate. The guidance given to the learners could be in the form of a flowchart.
Carboxylic acids are acidic due to the presence of the carboxyl group. They can react with bases to form salts and water. Alkenes, on the other hand, are not acidic.
How can you distinguish the alkene from the carboxylic acid?Alkenes have a carbon-carbon double bond (-C=C-), while carboxylic acids have a carboxyl group (-COOH). You can identify the functional group by looking at the molecular formula or by using spectroscopic techniques like infrared (IR) spectroscopy.
Carboxylic acids have higher boiling points than alkenes due to the presence of hydrogen bonding between carboxylic acid molecules.
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write the balanced nuclear equation for the alpha decay of each isotope. po84200 nuclear equation: thorium-229
The balanced nuclear equation for the alpha decay of polonium-84, and the nuclear equation for thorium-229 are:
Polonium-84 alpha decay:
^84Po --> ^4He + ^80Hg
In this equation, an alpha particle, which is a helium nucleus with a mass number of 4 and atomic number of 2, is emitted from the polonium-84 nucleus, resulting in the formation of a mercury-80 nucleus.
Thorium-229 nuclear equation:
^229Th
Thorium-229 is a stable isotope and does not undergo alpha decay or any other form of radioactive decay under normal circumstances.
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