Answer:
0.01228s⁻¹ = rate constant
Half-life = 56.4s
Explanation:
The first order reaction follows the equation:
ln[A] = -kt + ln[A]₀
Where [A] is amount of reactant after time t = 45.0%, k is rate constante and [A]₀ initial amount of reactant = 100%
ln[45%] = -k*65s + ln[100%]
-0.7985 = -k*65s
0.01228s⁻¹ = rate constant
Half-life is:
Half-life = ln2 / k
Half-life = 56.4s
An experiment was performed under identical conditions as yours. The absorbance of the penny solution was recorded as 0.219 absorbance units. A calibration plot of absorbance vs. concentration of Cu(II) (M) yielded the following trendline equation:
y= 11.589x - 0.0002
Required:
What is the concentration (mol/L) of the penny solution?
Answer:
Concentration C = 0.0189 mol/L
Explanation:
From the given information:
Let consider the formula used in calculating the concentration according to Beer's law:
[tex]\mathtt{A =\varepsilon \times L \times C}[/tex] --- (1)
here;
A = absorbance
ε = coefficient of molar absorptivity
L = path length
C = concentration (mol/L)
Also, from Beer law plot:
y = mx+b
where,
y represent absorbance A
b represents intercept
m represents the coefficient of molar absorptivity ε
and x represents the concentration(C).
replacing the substituted entities
A = ε × C + b ---- (2)
Making the concentration the subject of the above formula:
[tex]C = \dfrac{A-b}{\varepsilon}[/tex]----(3)
From y = 11.589x - 0.0002
A = 11.589 *C - 0.0002
Given that:
A = 0.219
∴
0.219 = 11.589 *C - 0.0002
0.219 + 0.0002 = 11.589 *C
C = 0.2192/11.589
C = 0.0189 mol/L
Fossils of a dinosaurs would most likely be found in
A)
conglomerate rock
B) sedimentary rock
C)
Igneous rock
D)
metamorphic rock
Answer:
b
Explanation:
Answer:
B
Explanation:
Do your structures resemble the following?
H-C=C-H
Answer:
For the HCCH Lewis structure you'll need to form a triple bond between the two carbon atoms. Hydrogen atoms only need two electrons for a full outer shell. There are a total of 10 valence electrons for the HCCH Lewis structure.
A new student is planning to use thin layer chromatography (TLC) for his research project. After setting up the apparatus the student forgets to place a lid on the TLC jar. He obtains poor results after running the TLC experiment. Which of the following can best explain his bad results?
A. The open system evaporates the solvent on the TLC plate
B. The open system prevents the evaporation of the solvent in the solution
C. The open system prevents the evaporation of the solvent on the TLC plate
D. The open system evaporates the solvent in the solution
Answer:
The open system evaporates the solvent in the solution
Explanation:
An open system is a system in which exchange of materials and energy can occur. If a TLC set up is left open, then the set up constitutes an open system.
During TLC, the sample is dotted on the plate and inserted into a suitable solvent. The solvent moves up the plate and achieves the required separation of the mixture.
Most of these solvents used used TLC are volatile organic compounds. Therefore, if the TLC set up is left open, the solvent will evaporate leading to poor results after running the TLC experiment.
Based on amino acid metabolism in mammals, classify the descriptions and amino acids is ketogenic or glucogenic. a. serine b. aspartate c. leucine d. converted to citric acid cycle intermediates e. converted to pyruvate f. converted to acetyl COA g. converted to fatty acids1) ketogenic2) glucogenic
Answer:
a. Serine is converted to pyruvate. It is glucogenic.
b. Aspartate is converted citric acid cycle intermediates. It is glucogenic.
c. Leucine is converted to AcetylCoA. It is ketogenic.
Explanation:
The degradation of amino acids usually account for a significant amount of energy production by the human body. The carbon skeletons of amino acids after deamination are either channelled to gluconeogenesis, ketogenesis or are completely oxidized to carbon dioxide and water.
The amino acids that are channelled to gluconeogenesis are said to be glucogenic. The glucogenic amino acids are those that are either degraded to ∝-ketoglutarate, succinylCoA, fumarate or oxaloacetate which are citric acid cycle intermediates that can be converted to glucose and glycogen. Also, amino acids that are degraded to pyruvate are glucogenic as pyruvate can be converted to glucose via oxaloacetate. Examples of these amino acids are serine which is converted to pyruvate and aspartate which is converted to the citric acid cycle intermediate, oxaloacetate.
On the other hand, amino acids that are channelled to ketogenesis are said to be ketogenic. The ketogenic amino acids are degraded to either acetylCoA or acetoacetylCoA. AcetylCoA and acetoacetylCoA are used in the formation of key one bodies. An example of a ketogenic amino acid is leucine which is converted both to AcetylCoA and acetoacetylCoA.
Concentration data is commonly monitored during a reaction to determine the order with respect to a reactant. Consider the types of observations listed, and determine which order is likely for that reactant. Assume all other factors are held constant. The reaction rate increases in direct proportion to the concentration of the reactant in solution.
a. The reaction rate is constant regardless of the amount of reactant in solution.
b. An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially.
Answer:
The reaction rate increases in direct proportion to the concentration of the reactant in solution - second order reaction
The reaction rate is constant regardless of the amount of reactant in solution - zero order reaction
An increase in the concentration of the reactant in solution causes the reaction rate to increase exponentially - first order reaction
Explanation:
In a second order reaction, the rate of reaction is directly proportional to the concentration of reactants. This implies that, reaction rate varies as the concentration of the reactant in solution varies.
For a zero order reaction, the rate of reaction is independent of the concentration of the reactants in solution. This means that reaction rate is constant regardless of the amount of reactant in solution.
For a first order reaction, the rate of reaction varies exponentially as the concentration of reactants. Hence, an increase or decrease in the concentration of the reactant in solution causes the reaction rate to increase or decrease exponentially.
examples of isotones
Answer:
Examples of isotones include carbon-12, nitrogen-13 and oxygen-14. These atoms all have six neutrons and six, seven and eight protons respectively. A mnemonic that can be used to differentiate isotones from isotopes and isobars is as follows: same Z (number of protons) = isotopes.
g) The set of quantum numbers for the 6th electron in fluorine atom.
Answer:
n=2, l= 1, m= 0, s = +1/2
Explanation:
An electron is described by four sets of quantum numbers;
I) principal quantum number (n)
ii) orbital quantum number (l)
iii)Magnetic quantum number (m)
iv) Spin quantum number (s)
The electronic configuration of fluorine is; 1s2 2s2 2p5
Hence, the sixth electron of fluorine is found in the 2p subshell where;
n=2, l= 1, m= 0, s = +1/2
on the right it says molecules H2o in questions 1 and 2
Answer:
For 1: 12.0 moles of water will contain [tex]7.2264\times 10^{24}[/tex] number of molecules
For 2: The given amount of water molecules will be present in 5.41 moles of water.
Explanation:
According to the mole concept:
1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules
For 1:We are given:
Moles of water = 12.0 moles
Using above concept:
If 1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules
So, 12.0 moles of water will contain = [tex](12.0\times 6.022\times 10^{23})=7.2264\times 10^{24}[/tex] number of molecules
Hence, 12.0 moles of water will contain [tex]7.2264\times 10^{24}[/tex] number of molecules
For 2:We are given:
Molecules of water = [tex]3.26\times 10^{24}[/tex] molecules
Using above concept:
If [tex]6.022\times 10^{23}[/tex] number of molecules are present in 1 mole of a compound
So, [tex]3.26\times 10^{24}[/tex] number of molecules will be present in = [tex]\frac{1mol}{6.022\times 10^{23}}\times 3.26\times 10^{24}=5.41[/tex] moles of water
Hence, the given amount of water molecules will be present in 5.41 moles of water.
What is black body radiation?
Explanation:
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why ionic compound are good conduct of electricity in their molten state ??
Answer:
Ionic compounds conduct electricity when molten (liquid) or in aqueous solution (dissolved in water), because their ions are free to move from place to place. Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move.
Explanation:
because their ions are free to move from place to place.
According to the law of conservation of matter, what cannot change during a chemical reaction?.
Answer:The law of conservation of mass states that in a chemical reaction mass is neither created nor destroyed. ... The carbon atom changes from a solid structure to a gas but its mass does not change. Similarly, the law of conservation of energy states that the amount of energy is neither created nor destroyed.
Explanation:
An organelle that is not found in this illustration of a cell would be
A. the cell wall
B. chromosome
C. mitochondria
D. the cell membrane
Answer:
The answer is cell wall
Explanation:
Because it is
Chair and Boat Conformers of Cyclohexane (C6H12). Note it is impossible to place all the carbons in the same plane without straining the bonds. Take two opposite carbons and pull both of them up to make one conformation and then pull one of them down to make the other conformation.
a. Can you interconvert one conformer into the other without breaking any bonds?
b. Explain why these represent conformers and not isomers.
Answer:
See explanation
Explanation:
Conformation refers to the various spatial arrangements of atoms in a molecule that result from free rotation across the carbon-carbon single bond.
There are two possible conformations of cyclohexane. They are; the chair and boat conformations.
We can convert the molecule from one conformation to another by rotation of single bonds.
These conformations are not isomers. Isomers are different molecules while conformers are different spatial arrangements of the same molecule obtained by rotation across carbon-carbon single bonds. Isomers are not obtained by rotation across carbon-carbon single bonds.
Hence, the chair and boat conformers of cyclohexane are obtained by rotation across the carbon-carbon single bond hence they are conformers and not isomers.
Calculate the mass of CaCL2 formed when 5 moles of chlorine reacts with calcium metal....
Answer:
555 g of CaCl₂
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
Ca + Cl₂ —> CaCl₂
From the balanced equation above,
1 mole of Cl₂ reacted to produce 1 mole of CaCl₂.
Next, we shall determine the number of mole of CaCl₂ produced by the reaction of 5 moles of Cl₂. This can be obtained as follow:
From the balanced equation above,
1 mole of Cl₂ reacted to produce 1 mole CaCl₂.
Therefore, 5 moles of Cl₂ will also react to produce 5 moles of CaCl₂.
Thus, 5 moles of CaCl₂ were obtained from the reaction.
Finally, we shall determine the mass of 5 moles of CaCl₂. This can be obtained as follow:
Mole of CaCl₂ = 5 moles
Molar mass of CaCl₂ = 40 + (35.5×2)
= 40 + 71
= 111 g/mol
Mass of CaCl₂ =?
Mass = mole × molar mass
Mass of CaCl₂ = 5 × 111
Mass of CaCl₂ = 555 g
Therefore, 555 g of CaCl₂ were obtained from the reaction.
Consider the following reaction at 298 K.
2 SO2(g) + O2(g) → 2 SO3(g)
An equilibrium mixture contains O2(g) and SO3(g) at partial pressures of 0.43 atm and 2.6 atm, respectively. Using data from Appendix 4, determine the equilibrium partial pressure of SO2 in the mixture.
______atm.
Answer and Explanation:
The reaction is in the gas phase, so the equilibrium constant is expressed in terms of the partial pressures (P) of the products and reactants, as follows:
[tex]Kp = \frac{P^{2}_{SO_{3} } }{P_{SO_{2}} ^{2}P_{O_{2}} }[/tex]
We have the following data:
P(SO₃) = 2.6 atm
P(O₂) = 0.43 atm
We need Kp for this reaction. We can assume that in Appendix 4 we found that Kp = 7 x 10²⁴.
Then, we introduce the data in the equilibrium constant expression to calculate the partial pressure f SO₂ (PSO₂), as follows:
[tex]P_{SO_{2} } = \sqrt{\frac{P_{SO_{3} } ^{2} }{Kp P_{O_{2} } } } = \sqrt{\frac{(2.6 atm)^{2} }{(7 x 10^{24)}(0.43 atm) } } = 1.5 x 10^{-12} atm[/tex]
Therefore, the partial pressure of SO₂ is 1.5 x 10⁻¹² atm (for the given Kp).
OT protons (d) (a) and (b)
3. Atoms of active elements have
(a) complete outermost orbit
(c) inert gas configuration
(b) incomplete outermost orbit
(d) complete dupletm
Answer:
A.
Explanation:
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Amphipathic molecules are ________; not able to interact via van der Waals forces. A) Polar only B) Nonpolar only C) Neither polar nor nonpolar D) Both polar and nonpolar
Answer:
D) Both polar and nonpolar.
Explanation:
Hello there!
In this case, according to the given statement, it turns out possible for us to bear to mind the fact the amphiphatic molecules are composed by two parts, the hydrophilic and the hydrophobic, being the former polar and the latter nonpolar as the example shown on the attached figure.
In such a way, we infer that the correct answer is D) Both polar and nonpolar.
Regards!
What is Markanikov rule?
Answer:
Regla de Markovnikov En fisicoquímica orgánica, la regla de Markovnikov es una observación respecto a la reacción de adición electrófila.Regla de Markovnikov En fisicoquímica orgánica, la regla de Markovnikov es una observación respecto a la reacción de adición electrófila.
Explanation:
One mole of
C
2
H
6
O
C
2
H
6
O has two moles of Carbon (C), six moles of Hydrogen (H) and one mole of Oxygen (O). How many moles of Hydrogen is in 0.2 moles of
C
2
H
6
O
C
2
H
6
O?
Answer:
c
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Equilibrium constants for gases can be expressed in terms of concentrations, Kc, or in terms of partial pressures, Kp. Which one of the following statements regarding Kc and Kp is correct?
a. Kc and Kp are equal when all stoichiometric coefficients in the balanced reaction equation equal one.
b. Kc and Kp are equal when the conditions are standard (P= 1 atm, T=298 K)
c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
d. Kc and Kp can never be equal.
e. Kc and Kp have the same values but different units.
Answer:
c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to write the relationship between Kc and Kp in terms of the temperature and the change in the stoichiometric coefficients:
[tex]Kp=Kc(RT)^{\Delta \nu}[/tex]
Thus, we can see that the Kp=Kc just when Δυ=0, which is the sum of the coefficients of products minus that of reactants; and therefore, the correct answer will be c. Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
Regards!
Calculate the mass of 2.5 mols of Sodium Oxide
Answer:
8
Explanation:
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If chromium(II) iodide is dissolved in water you can say that the equilibrium concentrations of chromium(II) and iodide ions are: __________
Answer:
See explanation.
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to set up the equilibrium reaction by which chromium (II) iodide is ionized as follows:
[tex]CrI_2(s)\rightarrow Cr^{2+}(aq)+2I^-(aq)[/tex]
Thus, it is possible to notice that the the moles, and therefore concentrations, of chromium(II) and iodide ions are going to be different, by a factor of 2 due to the mole ratio in the aforementioned chemical equation.
Regards!
Diazomethane has the molecular formula CH2N2. Draw the preferred Lewis structure for diazomethane and assign formal charges to all atoms, if any.
Answer:
See explanation
Explanation:
We define the formal charge on an atom in a molecule as the charge it carries assuming that electrons in all chemical bonds of the molecule were shared equally between atoms irrespective of the electronegativity of each atom.
The formula for calculating the formal charge on an atom in a molecule is;
Formal Charge = [number of valence electrons on neutral atom] – [(number of lone electron pairs) + (½ number of bonding electrons)] ·
The formal charge on the two nitrogen atoms in diazomethane is obtained as follows;
Middle nitrogen atom = 5 – 8/2 – 0 = +1
Last nitrogen atom = 5 – 4/2 – 4 = –1
The Lewis structure of the molecule is shown in the image attached.
What is the conjugate base of the following acids:
1. HCIO,
2. PH4^+
Answer:
ECUACIÓN:HClO 2 + H 2O → ClO− 2 + H 3O
ACIDO: HClO2
BASECONJUGADA:ClO-2
Explanation:
If D+2 would react with E-", what do you predict to be the formula?
OD 2E
O DE
OD 2E 2
O DE 2
Answer:DE2
Explanation:
Why is there a huge diversity of substances?
A. Atoms can combine in many ways to form various compounds
and molecules.
B. Any element can combine with any other element.
C. Atoms break apart to form new types of atoms during chemical
reactions.
D. There is an unlimited number of elements.
A. Atoms can combine in many ways to form various compounds
and molecules.
Which reaction produces an insoluble product?
A
2KI + Pb(NO )2 → → PbI, + 2KNO
B
2AgNO3 + Ca(CH,02)2 + Ca(NO3)2 + 2AgC,H,O,
C
3BaCl2 + ALLS
→ 2AlCl3 + 3BaS
.
D
SrBr, + Mg(OH)2 → MgBr, + Sr(OH)2
Answer: The correct option is A).
Explanation:
Precipitation reaction is defined as the reaction where a solid precipitate (solid substance) is formed at the end of the reaction. It is insoluble in water.
For the given chemical reactions:
A): [tex]2KI+Pb(NO_3)_2\rightarrow PbI_2+2KNO_3[/tex]
The iodide of lead is generally insoluble in water. Thus, lead iodide is a precipitate.
B): [tex]2AgNO_3+Ca(CH_3COO)_2\rightarrow Ca(NO_3)_2+2CH_3COOAg[/tex]
The nitrates and acetates of all metals are soluble in water.
C): [tex]3BaCl_2+Al_2S_3\rightarrow 2AlCl_3+3BaS[/tex]
The sulfide of barium is soluble in water.
D): [tex]SrBr_2+Mg(OH)_2\rightarrow MgBr_2+Sr(OH)_2[/tex]
The hydroxide of strontium is soluble in water.
Hence, the correct option is A).
Sodium fluoroacetate (NaO₂C₂H₂F) is a common poison used in New Zealand to control invasive species, such as rats. It can be prepared by the substitution of a C-Cl bond in sodium chloroacetate (NaO₂C₂H₂Cl) for a C-F bond. What is the approximate enthalpy change for this substitution reaction on a 1.500 mole sample, based on the following bond energies?
C-Cl = 339.0 kJ/mol
C-F = 485.0 kJ/mol
Answer:
-219
Explanation:
1.5(339) - 1.5(485) = -219
The approximate enthalpy change for this substitution reaction is -219 kJ.
In the case of this substitution reaction, we need to find the enthalpy change when NaO₂C₂H₂Cl is converted to NaO₂C₂H₂F.
This reaction involves the breaking of the C-Cl bond and the formation of the C-F bond.
We have to subtract the bond energy of the C-F bond from that of the C-Cl bond and multiply by the number of moles involved.
So we will have;
ΔH= 1.500 mole [339.0 kJ/mol - 485.0 kJ/mol]
ΔH= -219 kJ
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Half-life
Nickel-63 has a half life of 92 hours. If a 1000 gram
sample decayed for 368 years
, how much
Nickel -63 remains?