Answer: The correct option is A) 8.97
Explanation:
To calculate the [tex]K_b[/tex] of a reaction, we use the equation:
[tex]K_a\times K_b=10^{-14}[/tex]
where,
[tex]K_a[/tex] = acid dissociation constant of acetic acid = [tex]1.86\times 10^{-5}[/tex]
[tex]K_b[/tex] = base dissociation constant
Putting values in above equation, we get:
[tex](1.86\times 10^{-5})\times K_b=10^{-14}\\\\K_b=\frac{10^{-14}}{1.86\times 10^{-5}}=5.37\times 10^{-10}[/tex]
To calculate the hydroxide ion concentration of conjugate base, we use the equation:
[tex][OH^-]=\sqrt{K_b\times \text{[Conjugate base]}}[/tex]
where,
[Conjugate base] = 0.10 M
Putting values in above equation, we get:
[tex][OH^-]=\sqrt{(5.37\times 10^{-10})\times 0.1}[/tex]
[tex][OH^-]=7.33\times 10^{-6}[/tex]
To calculate the pOH of the solution, we use the equation:
[tex]pOH=-\log [OH^-][/tex]
[tex]pOH=-\log (7.33\times 10^{-6})[/tex]
[tex]pOH=5.03[/tex]
To calculate the pH of the solution, we use the equation:
pH + pOH = 14
pH + 5.03 = 14
pH = (14 - 5.03) = 8.97
Hence, the correct option is A) 8.97
When of alanine are dissolved in of a certain mystery liquid , the freezing point of the solution is less than the freezing point of pure . Calculate the mass of potassium bromide that must be dissolved in the same mass of to produce the same depression in freezing point. The van't Hoff factor for potassium bromide in .
The question is incomplete, the complete question is:
When 177. g of alanine [tex](C_3H_7NO_2)[/tex] are dissolved in 800.0 g of a certain mystery liquid X, the freezing point of the solution is [tex]5.9^oC[/tex] lower than the freezing point of pure X. On the other hand, when 177.0 g of potassium bromide are dissolved in the same mass of X, the freezing point of the solution is [tex]7.2^oC[/tex] lower than the freezing point of pure X. Calculate the van't Hoff factor for potassium bromide in X.
Answer: The van't Hoff factor for potassium bromide in X is 1.63
Explanation:
Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.
The expression for the calculation of depression in freezing point is:
[tex]\Delta T_f=i\times K_f\times m[/tex]
OR
[tex]\Delta T_f=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}[/tex] ......(1)
When alanine is dissolved in mystery liquid X:[tex]\Delta T_f=5.9^oC[/tex]
i = Vant Hoff factor = 1 (for non-electrolytes)
[tex]K_f[/tex] = freezing point depression constant
[tex]m_{solute}[/tex] = Given mass of solute (alanine) = 177. g
[tex]M_{solute}[/tex] = Molar mass of solute (alanine) = 89 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent = 800.0 g
Putting values in equation 1, we get:
[tex]5.9=1\times K_f\times \frac{177\times 1000}{89\times 800}\\\\K_f=\frac{5.9\times 89\times 800}{1\times 177\times 1000}\\\\K_f=2.37^oC/m[/tex]
When KBr is dissolved in mystery liquid X:[tex]\Delta T_f=7.2^oC[/tex]
i = Vant Hoff factor = ?
[tex]K_f[/tex] = freezing point depression constant = [tex]2.37^oC/m[/tex]
[tex]m_{solute}[/tex] = Given mass of solute (KBr) = 177. g
[tex]M_{solute}[/tex] = Molar mass of solute (KBr) = 119 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent = 800.0 g
Putting values in equation 1, we get:
[tex]7.2=i\times 2.37\times \frac{177\times 1000}{119\times 800}\\\\i=\frac{7.2\times 119\times 800}{2.37\times 177\times 1000}\\\\i=1.63[/tex]
Hence, the van't Hoff factor for potassium bromide in X is 1.63
Draw the Lewis structure of NCl3NCl3 . Include lone pairs. Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Select Draw Rings More Erase Cl N
Answer:
See explanation and image attached
Explanation:
Nitrogen trichloride NCl3 contains one nitrogen and three chlorine atoms. Each chlorine atom has three lone pairs of electrons while nitrogen has one lone pair of electrons.
The molecule geometry of the molecule is trigonal pyramidal while it's electron domain geometry is tetrahedral. Nitrogen is the central atom and is found in sp3 hybridization.
There is no formal charge on the molecule.
which chemical can be added to an acidic soil to make it neutral it's easy
Answer:
Boiled a added acidic solution for Lowe's home improvement for car insurance cost the Africa map of the soul
A certain liquid has a normal freezing point of and a freezing point depression constant . Calculate the freezing point of a solution made of of iron(III) chloride () dissolved in of . Round your answer to significant digits.
The question is incomplete, the complete question is:
A certain liquid X has a normal freezing point of [tex]0.80^oC[/tex] and a freezing point depression constant [tex]K_f=7.82^oC.kg/mol[/tex] . Calculate the freezing point of a solution made of 81.1 g of iron(III) chloride () dissolved in 850. g of X. Round your answer to significant digits.
Answer: The freezing point of the solution is [tex]-17.6^oC[/tex]
Explanation:
Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.
The expression for the calculation of depression in freezing point is:
[tex]\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times m[/tex]
OR
[tex]\text{Freezing point of pure solvent}-\text{Freezing point of solution}=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}[/tex] ......(1)
where,
Freezing point of pure solvent = [tex]0.80^oC[/tex]
Freezing point of solution = [tex]?^oC[/tex]
i = Vant Hoff factor = 4 (for iron (III) chloride as 4 ions are produced in the reaction)
[tex]K_f[/tex] = freezing point depression constant = [tex]7.82^oC/m[/tex]
[tex]m_{solute}[/tex] = Given mass of solute (iron (III) chloride) = 81.1 g
[tex]M_{solute}[/tex] = Molar mass of solute (iron (III) chloride) = 162.2 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent (X) = 850. g
Putting values in equation 1, we get:
[tex]0.8-(\text{Freezing point of solution})=4\times 7.82\times \frac{81.1\times 1000}{162.2\times 850}\\\\\text{Freezing point of solution}=[0.8-18.4]^oC\\\\\text{Freezing point of solution}=-17.6^oC[/tex]
Hence, the freezing point of the solution is [tex]-17.6^oC[/tex]
Can the properties of different substances in a mixture be used to separate them?
Answer: here you go
Explanation:
Physical properties of the substances in a mixture are different, so this allows the substances to be separated. Think about the example of a mixture of salt water.
Answer:
Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions, and colloids. The components of a mixture retain their own physical properties. These properties can be used to separate the components by filtering, boiling, or other physical processes.
Explanation:
g Ions B and C react to form the complex BC. If 35.0 mL of 1.00 M B is combined with 35.0 mL of 1.00 M C, 0.00500 mol of BC is formed. Determine the equilibrium constant for this reaction.
Answer:
Kf = 0.389.
Explanation:
Hello there!
In this case, it turns out possible for us to solve this problem by firstly writing the equilibrium chemical equation and equilibrium expression for the formation of this complex:
[tex]B+C\rightleftharpoons BC\\\\Kf=\frac{[BC]}{[B][C]}[/tex]
Thus, we firstly calculate the concentrations at equilibrium, knowing that the reaction extent in this case is 0.00500mol (same as the formed moles of BC):
[tex][B]=[C]=\frac{0.0350L*1.00mol/L-0.00500mol}{0.0700L} =0.429M[/tex]
[tex][BC]=\frac{0.00500mol}{0.0700L} =0.0714M[/tex]
And finally, the equilibrium constant:
[tex]Kf=\frac{0.0714}{[0.429][0.429]}\\\\Kf=0.389[/tex]
Regards!
A length of copper wire has a mass of 6.19 g. How many moles of copper are in the wire? moles
Answer:
molar mass of copper = 63.55 g/mol
( 1 mol of copper)
6.19 g copper × ( 63.55g copper )
0.0975 moles
A certain alkyl halide is reacted with OH- to form an alcohol. The alkyl halide is optically active but the product(s) is/are optically inactive. Which of the following could be the reactant?a) 3-bromo-3-methylhexane.b) 1-chlorobutane.c) 2-bromo-2-methylbutane.d) 3-bromo-2,3,4-trimethypentane.
Answer:
a. 3-brumo - 3-methylhexane
Explanation:
Alkyl Halides can undergo substitution reactions. Nucleophiles are electron rich species and has negative charge while Electrophiles are electron deficient species which carry positive charge. Alkyl halide which have polar carbon atom are electrophiles.
Give the IUPAC name for the following alkyl group, and classify it as primary, secondary, or tertiary.
CH3(CH2)9CH2
Answer:
Give the IUPAC name for the following alkyl group, and classify it as primary, secondary, or tertiary.
CH3(CH2)9CH2
Explanation:
In the given alkyl group there are eleven carbon atoms.
So, the alkyl group name is:
n-undecyl.
Pimary carbon is the one which is attached only one other carbon atom,group.
Secondary carbon is the one which is attached to two carbons.
Thertiary carbon is the one which is attached to three other carbons.
In the given alkyl group,
the primary,secondary alkyl groups are shown below:
There is no tertiary carbon atom in the given molecule.
what is the atomic structure of an element that has atomic number of 11 and neutron number of 12.
Answer:
See explanation
Explanation:
The atomic number refers to the number of protons in the nucleus, it also tells us the number of electrons in the neutral atom since the atom is electrically neutral because the number of protons and electrons are equal.
If an atom has the atomic number 11, then the electrons in the atom are arranged in the shells in the order; 2, 8, 1.
Two electrons are found in the innermost shell, eight electrons are found in the next shell and one electron is found on the outermost shell.
The nucleus of the atom is composed of a total of 23 nucleons; 11 protons and 12 neutrons.
why is it preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride
Answer:
Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
What is Dehydration ?A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.
Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,
Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
Learn more about reactions here ;
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Which statement shows why mass is conserved for this reaction? 2Mg + O2 → 2MgO
Answer:
The same number of each atom are on both sides of the equation.
The Law of conservation of mass states that matter is neither destroyed nor created in a chemical reaction. Therefore, the mass of the reactants will be equal to the mass of the products in a chemical reaction. According to the law matter is neither created nor destroyed in a chemical reaction.
Help on both please and thanks
Answer:
1. Granite
2. 535.5J
Explanation:
1. The lower the specific heat capacity of a substance, which is the amount of heat needed to raise the temperature of a particular mass of substance by 1 °C or K, the slower the rate at which the temperature is raised.
In this question 1, the substance with the lowest specific heat capacity in J/gK is GRANITE, hence, it will raise temperature the slowest.
2. Using the formula as follows:
Q = m × c × ∆T
Where;
c = specific heat capacity
Q = amount of heat (J)
m = mass of substance
∆T = change in temperature (°C)
m = 35g, c = 0.45 J/g°C, ∆T = 54°C - 20°C = 34°C
Q = 35 × 0.45 × 34
Q = 535.5J
which effect of long-term environmental change is the driving force behind evolution?
Answer:
climate change
Explanation:
climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.
How is the atomic mass of an element calculated?
Answer:
Mass number (A) is the number of nucleons (proton and neutron) present in a atom.
Explanation:
electrons don't cout since they are thousandth's of the mass of protons or neutrons
Question 10 What is the UPAC name for this compound? CH3-----CHO
Answer:
Ethanal or acetaldehyde
Explanation:
Ethanal, also called acetaldehyde is the second member of the alkanal or aldehyde group of hydrocarbons, which have a functional group of -CHO. The -CHO functional group characterizes every member to this group and makes them behave chemically similar.
However, the second member of this aldehyde group with a formula of CH3----CHO, has a methyl group (CH3) attached to the functional group, hence, it is called ETHANAL OR ACETALDEHYDE.
g A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is __________ compared to a 300 mOsM solution and ___________ compared to a cell with 300 mOsM (non-penetrating solutes) interior.
Answer:
A solution contains 100mM NaCl, 20mM CaCl2, and 20mM urea. We would say this solution is hypotonic compared to a 300 mOsM solution and hypotonic compared to a cell with 300 mOsM (non-penetrating solutes) interior.
Explanation:
The osmolarity is calculated from the molar concentration of the active particles in the solution. We have a solution that is composed of NaCl, CaCl₂ and urea.
When they are dissolved in water, they dissociate into particles as follows:
NaCl → Na⁺ + Cl⁻ (2 particles per compound)
CaCl₂ → Ca²⁺ + 2 Cl⁻ (3 particles per compound)
urea: not dissociation (1 particle per compound)
Then, we have to calculate the osmolarity of the solution. We multiply the molarity of each compound by the number of particles produced by the compound in water:
Osm = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) + (20 mM urea x 1) = 280 mOsm
Compared with 300 mOsm, 280 mOsm has a lower osmolarity, so it is a hypotonic solution.
To compare with a cell's osmolarity, we have to consider only the non-penetrating solutes. Urea is considered a penetrating solute for mammalian cells. So, the osmolarity of non-penetrating solutes (NaCl and CaCl₂) is calculated as:
Osm (non-penetrating solutes) = (100 mM NaCl x 2) + (20 mM CaCl₂ x 3) = 260 mOsm
Therefore, we have:
Compared to 300 mOsm solution ⇒ 280 mOsm solution is a hypotonic solution
Compared to a cell with 300 mOsm ⇒ 260 mOsm solution is hypotonic
Which of the following is NOT likely to cause a change in average annual temperatures on Earth?
a. Human activity. b. Solar eclipses.
c. Photosynthesis by plants and algae. d. Strength of solar radiation.
Answer:
i think C is the answer
Explanation:
The change in average annual temperatures on earth will be due to "photosynthesis by plants and algae".
What is photosynthesis?Photosynthesis can be defined as a process in which plants, as well as other organisms, as well as other organisms, utilize to transform sunlight into chemical energy which can then be released to power the organism's activities using cellular respiration.
What is plants?
Plants seem to be mostly photosynthetic eukaryotes belonging to the plantae kingdom.
Therefore, photosynthesis cannot change in average annual temperature on Earth.
To know more about photosynthesis.
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the intrument that tells both the speed and direction of the wind is the?
Answer:
anemometer
Explanation:
The instrument that is being described is called an anemometer. This is a device that has 4 ladel like objects that allow the wind to hit it, causing it to spin. The force of the spin allows meteorologists to calculate the speed of the wind. On top of this device is usually an arrow which can rotate around the device with the wind and point in the direction that the wind is blowing. Using a N, NE, E, SE, S, SW, W, and NW direction.
Match the name of each gas law to the properties it compares. (3 points)
1. Boyle's law
2. Avogadro's law
3. Gay-Lussac's law
a. Volume and moles
b. Pressure and volume
c. Pressure and temperature
Answer:
1. B
2. A
3. C
Explanation:
1. Boyle's law is one of the gas laws that states that the pressure of a gas is inversely proportional to its volume at a constant temperature. PV = K. Hence, this gas law compares the properties of the pressure (P) and the volume (V)
2. Avogadro's law states that the volume of a gas is directly proportional to the number of molecules of that gas, at a constant temperature and pressure. K = Vn. Hence, this gas law compares the properties of the number of moles (n) and the volume (V).
3. Gay-Lussac's law states that the pressure of a gas is directly proportional with the temperature of the gas at a constant volume. K = PT. Hence, this law compares the properties of the pressure (P) and the temperature (T)
The properties compared by Boyle's law are pressure and volume, Avogadro's law is volume and moles, and Gay-Lussac's law is pressure and temperature.
What are the variations of ideal gas law?The ideal gas has the absence of interatomic collisions and follows the ideal gas equation.
The ideal gas law at constant pressure and temperature is termed Boyle's and Gay Lussac's law. The laws can be given as:
Boyle's law was the nature of ideal gas at a constant temperature and compares the pressure and volume of the gas.Avogadro's law was the ideal nature of gas, with the moles of gas and volume in specific value at constant temperature and pressure.Gay-Lussac's law compares the pressure and temperature of the gas at constant volume.Learn more about ideal gas laws, here:
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What is the name of the functional group that is made of a carbon atom
double bonded to an oxygen atom?
O A. Carbonyl
O B. Ether
O c. Alcohol
O D. Ester
What is the concentration of a solution in which 15 grams of sugar is dissolved in 0.2 L of water?
Answer:
0.2 M
Explanation:
Step 1: Given data
Mass of sugar (sucrose): 15 gVolume of water: 0.2 L (we will assume it is the volume of the solution)There are different ways to express the concentration of a solution. We will calculate molarity, which is one of the most used.
Step 2: Calculate the moles of sucrose
The molar mass of sucrose is 342.3 g/mol.
15 g × 1 mol/342.3 g = 0.044 mol
Step 3: Calculate the molarity of the solution
Molarity is equal to the moles of solute divided by the liters of solution.
M = 0.044 mol/0.2 L = 0.2 M
What is the Ke of the 20 gram shoe as it falls to the ground at 6 m/s?
PLEASE HELP ITS 7TH GRADE SCIENCE!!!
For the iron thiocyanate system, what is the value of the equilibrium constant, Kc, if the following are the concentrations of all species present. Provide your answer to three digits after the decimal.
FeSCN2+ 0.501
Fe3+ 0.494
SCN- 0.639
Answer:
Kc = 0.630
Explanation:
The equilibrium of the thiocyanate system occurs as follows:
FeSCN²⁺(aq) ⇄ Fe³⁺(aq) + SCN⁻(aq)
And equilibrium constant, kc, is:
Kc = [SCN⁻] [Fe³⁺] / [FeSCN²⁺]
Replacing with the gven concentrations:
Kc = 0.639M*0.494M / 0.501M
Kc = 0.630phương pháp VI PHÂN ĐỒ THỊ để xác định bậc phản ứng
Answer:
mwlooy kagabi jal
64 JAHA VI PHÂN KAY
10-Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solvent. What is the molarity of a solution containing 9.478 grams of Rucl, in enough water to make 1.00 L of solution?
Answer:
0.0457 M
Explanation:
Concentration is the amount of a substance in a predefined volume of space. The basic measurement of concentration in chemistry is molarity or the number of moles of solute per liter of solution. What is the molarity of a solution containing 9.478 grams of RuCl₃, in enough water to make 1.00 L of solution?
Step 1: Given data
Mass of RuCl₃ (solute): 9.478 gVolume of solution: 1.00 LStep 2: Calculate the moles corresponding to 9.478 g of RuCl₃
The molar mass of RuCl₃ is 207.4 g/mol.
9.478 g × 1 mol/207.4 g = 0.04570 mol
Step 3: Calculate the molarity of the solution
We will use the definition of molarity.
M = moles of solute / liters of solution
M = 0.04570 mol / 1.00 L = 0.0457 M
The hydrogen fluoride molecule, HF, is more polar than a water molecule, H2O (for example, has a greater dipole moment), yet the molar enthalpy of vaporization for liquid hydrogen fluoride is lesser than that for water. Explain.
Answer:
Water forms more hydrogen bonds than HF
Explanation:
The answer to this question goes back to the idea of hydrogen bonding. Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom such as fluorine or oxygen.
However, in HF, there are three lone pairs of electrons on fluorine atom and one hydrogen atom bonded to fluorine.
In H2O, there are two lone pairs of electrons on oxygen atom and two hydrogen atoms bonded to oxygen. This simply means that water can form four hydrogen bonds while HF only forms two hydrogen bonds.
This implies that H2O molecules possess more hydrogen bonding than HF molecules. Hence, the molar enthalpy of vaporization for liquid hydrogen fluoride is lesser than that for water.
Determine whether or not each ion contributes to water hardness.
a. Ca2+
b. (HCO)3^-
c. K+
d. Mg2+
Answer: The ion that contribute to water hardness are:
--> a. Ca2+
--> b. (HCO)3^- and
--> c. Mg2+
While K+ DOES NOT contribute to water hardness.
Explanation:
WATER in chemistry is known as a universal solvent. This is so because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions. It is composed of elements such as hydrogen and oxygen in the combined ratio of 2:1.
Water is said to be HARD if it does not lather readily with soap. There are two types of water hardness:
--> Permanent hardness: This is mainly due to the presence of CALCIUM and MAGNESIUM ions in the form of soluble tetraoxosulphate(VI) and chlorides. These ions are removed by adding washing soda or caustic soda.
--> Temporary hardness: This is due to the presence of calcium HYDROGENTRIOXOCARBONATES. It can be removed by boiling and using slaked lime.
Therefore from the above given ions, Ca2+,(HCO)3^- and Mg2+ contributes to water hardness.
..............................................................................................
The specific rate constant, k, for radioactive beryllium–11 is 0.049 s–1. What mass of a 0.500 mg sample of beryllium–11 remains after 28 seconds? This reaction was found to be first order.
Answer: The mass of sample that remained is 0.127 mg
Explanation:
The integrated rate law equation for first-order kinetics:
[tex]k=\frac{2.303}{t}\log \frac{a}{a-x}[/tex] ......(1)
Given values:
a = initial concentration of reactant = 0.500 mg
a - x = concentration of reactant left after time 't' = ?mg
t = time period = 28 s
k = rate constant = [tex]0.049s^{-1}[/tex]
Putting values in equation 1:
[tex]0.049s^{-1}=\frac{2.303}{28s}\log (\frac{0.500}{(a-x)})\\\\\log (\frac{0.500}{(a-x)})=\frac{0.049\times 28}{2.303}\\\\\frac{0.500}{a-x}=10^{0.5957}\\\\frac{0.500}{a-x}=3.94\\\\a-x=\frac{0.500}{3.942}=0.127mg[/tex]
Hence, the mass of sample that remained is 0.127 mg