Q: A kinetics experiment for the reaction $$N_2(g) + 3Cl_2(g$$) \rightarrow 2NCl_3(g)$$ yields the following initial rates: Trial I: $$[$$N_2$$] = 0.200\ \text{M}$$, $$[$$Cl_2$$] = 0.300\ \text{M}$$, rate = 0.0100$$\ \text{M/min}$$ Trial II: $$[$$N_2$$] = 0.200\ \text{M}$$, $$[$$Cl_2$$] = 0.600\ \text{M}$$, rate = 0.0200$$\ \text{M/min}$$ Trial III: $$[$$N_2$$] = 0.400\ \text{M}$$, $$[$$Cl_2$$] = 0.300\ \text{M}$$, rate = 0.0200$$\ \text{M/min}$$ What is the correct rate law for this reaction?

$$\text{rate} = k[N_2$][Cl_2$]$$

Q: A student mixes 17.0 mL of $$7.50 \times 10$$^{-4}$$\ \text{M}$$ crystal violet (CV) solution and 3.00 mL of $$0.30\ \text{M}$$ NaOH solution. What is the initial $$[OH^-]$$ concentration after mixing?

$$4.29 \times 10$$^{-2}$$\ \text{M}$$

Q: A calibration curve for FeSCN$$^{2+} is $$given by $$y = 5521x + 0.043$$, where $$y is $$absorbance and $$x is $$concentration in M. If a sample has an absorbance of 0.187, what is the FeSCN$$^{2+}$$ concentration?

$$2.61 \times 10$$^{-3}$$\ \text{M}$$

Q: A student is preparing a standard solution of FeSCN$$^{2+} by $$mixing $$10.0\ \text{mL} of$$ $$0.00100\ \text{M} Fe(NO$_3$$)$$_3$$ and $$10.0\ \text{mL} of$$ $$0.00200\ \text{M}$$ KSCN$$. What is the final FeSCN$$^{2+}$$ concentration at equilibrium, assuming all SCN$$^-$ is converted?

$$5.21 \times 10$$^{-4}$$\ \text{M}$$

Q: A student is preparing a buffer solution using acetic acid and sodium acetate. Which equation should be used to calculate the pH of the buffer?

$$\text{pH} = pK_a + \log \frac{[A^-]}{[HA]}$$

Question 1

A kinetics experiment for the reaction $$N_2(g) + 3Cl_2(g$$) ightarrow 2NCl_3(g)$$ yields the following initial rates:
Trial I: $$[$$N_2$$] = 0.200\ 	ext{M}$$, $$[$$Cl_2$$] = 0.300\ 	ext{M}$$, rate = 0.0100$$\ 	ext{M/min}$$
Trial II: $$[$$N_2$$] = 0.200\ 	ext{M}$$, $$[$$Cl_2$$] = 0.600\ 	ext{M}$$, rate = 0.0200$$\ 	ext{M/min}$$
Trial III: $$[$$N_2$$] = 0.400\ 	ext{M}$$, $$[$$Cl_2$$] = 0.300\ 	ext{M}$$, rate = 0.0200$$\ 	ext{M/min}$$
What is the correct rate law for this reaction?

Accepted Answer

$$	ext{rate} = k[N_2$][Cl_2$]$$

Question 2

A student mixes 17.0 mL of $$7.50 	imes 10$$^{-4}$$\ 	ext{M}$$ crystal violet (CV) solution and 3.00 mL of $$0.30\ 	ext{M}$$ NaOH solution. What is the initial $$[OH^-]$$ concentration after mixing?

Accepted Answer

$$4.29 	imes 10$$^{-2}$$\ 	ext{M}$$

Question 3

A calibration curve for FeSCN$$^{2+} is $$given by $$y = 5521x + 0.043$$, where $$y is $$absorbance and $$x is $$concentration in M. If a sample has an absorbance of 0.187, what is the FeSCN$$^{2+}$$ concentration?

Accepted Answer

$$2.61 	imes 10$$^{-3}$$\ 	ext{M}$$

Question 4

A $$0.250\ 	ext{M}$$ solution of a weak acid is $$1.25\%$$ dissociated. What is the percent ionization of this acid?

Accepted Answer

$$1.25\%$$

Question 5

A $$0.250\ 	ext{M}$$ solution of a weak base has a pH of $$11.28. $$What is the $$K_b of $$this base?

Accepted Answer

$$3.5 	imes 10$$^{-3}$$

Question 6

A $$0.585\ 	ext{g}$$ sample of toilet cleaner is titrated with $$0.1327\ 	ext{M}$$ NaOH. The titration curve shows an equivalence point at $$16.34\ 	ext{mL} of $$NaOH. How many moles of HCl are in the sample?

Accepted Answer

$$2.17 	imes 10$$^{-3}$$ mol

Question 7

A $$0.585\ 	ext{g}$$ sample of toilet cleaner is titrated with $$0.1327\ 	ext{M}$$ NaOH. The titration curve shows an equivalence point at $$16.34\ 	ext{mL} of $$NaOH. What is the percent by mass of HCl in the sample? (Molar mass of HCl = $$36.46\ 	ext{g/mol})$$

Accepted Answer

$$13.6\%$$

Question 8

A student is preparing a standard solution of FeSCN$$^{2+} by $$mixing $$10.0\ 	ext{mL} of$$ $$0.00100\ 	ext{M} Fe(NO$_3$$)$$_3$$ and $$10.0\ 	ext{mL} of$$ $$0.00200\ 	ext{M}$$ KSCN$$. What is the final FeSCN$$^{2+}$$ concentration at equilibrium, assuming all SCN$$^-$ is converted?

Accepted Answer

$$5.21 	imes 10$$^{-4}$$\ 	ext{M}$$

Question 9

A $$20.00\ 	ext{mL}$$ sample of $$0.1234\ 	ext{M}$$ monoprotic weak acid is titrated with NaOH of unknown concentration. The equivalence point is reached at $$24.00\ 	ext{mL} of $$NaOH. What is the concentration of the NaOH solution?

Accepted Answer

$$0.1027\ 	ext{M}$$

Question 10

A $$20.00\ 	ext{mL}$$ sample of $$0.1234\ 	ext{M}$$ monoprotic weak acid is titrated with NaOH. The initial pH of the acid is $$3.17. $$What is the $$K_a of $$this weak acid?

Accepted Answer

$$1.8 	imes 10$$^{-4}$$

Question 11

A solution is prepared by mixing $$16.0\ 	ext{mL} of$$ $$0.025\ 	ext{M} Cu(NO$_3$$)$$_2$$ and $$16.0\ 	ext{mL} of$$ $$0.015\ 	ext{M}$$ KIO$$_3. $$The solution is heated until saturated, then cooled. The equilibrium concentration of Cu(IO$$_3$$)$$_2 is$$ $$1.7 	imes 10$$^{-4}$$\ 	ext{M}. $$What is the experimental $$K_{sp} of Cu(IO$_3$$)$$_2$$?

Accepted Answer

$$5.3 	imes 10$$^{-7}$$

Question 12

Which of the following best describes the effect of increasing the wavelength of light used in a colorimeter when measuring the absorbance of a blue solution?

Accepted Answer

Absorbance will decrease as the wavelength moves away from the absorption maximum.

Question 13

A student is analyzing the kinetics of a reaction and finds that doubling the concentration of reactant Z doubles the rate, while doubling the concentration of reactant Y has no effect. What is the order of the reaction with respect to Z and Y?

Accepted Answer

First order in Z, zero order in Y

Question 14

A student is preparing to work in the chemistry lab. Which of the following is NOT an appropriate safety practice?

Accepted Answer

Wearing sandals or flip-flops

Question 15

A solution is prepared by mixing $$10.0\ 	ext{mL} of$$ $$0.00100\ 	ext{M} Fe(NO$_3$$)$$_3$$ and $$10.0\ 	ext{mL} of$$ $$0.00200\ 	ext{M}$$ KSCN. What is the limiting reagent?

Accepted Answer

Fe(NO$$_3$$)$$_3$$

Question 16

A student is asked to calculate the pH of a $$0.250\ 	ext{M}$$ solution of a weak acid that is $$1.25\%$$ dissociated. What is the correct pH?

Accepted Answer

$$2.52$$

Question 17

A student is analyzing a reaction and finds that the rate law is $$	ext{rate} = k[OH^-][CV]. If$$ $$[OH^-] is $$doubled and $$[CV] is $$halved, what happens to the rate?

Accepted Answer

The rate remains the same

Question 18

A student is using a spectrophotometer to measure the concentration of a colored solution. Which of the following best describes the relationship between absorbance (A), molar absorptivity ($$\epsilon$$), path length (l), and concentration (c)?

Accepted Answer

$$A = \epsilon l c$$

Question 19

A student is analyzing the titration curve of a weak acid with a strong base. At the half-equivalence point, what is the relationship between pH and $$pK_a$$?

Accepted Answer

$$	ext{pH} = pK_a$$

Question 20

A student is preparing a buffer solution using acetic acid and sodium acetate. Which equation should be used to calculate the pH of the buffer?

Accepted Answer

$$	ext{pH} = pK_a + \log \frac{[A^-]}{[HA]}$$

General Chemistry Exam Study Guide: Chemical Kinetics, Equilibrium, Acid-Base Chemistry, and Laboratory Calculations

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