Seven Lakes Invitational — Chemistry Lab

Chemistry Lab · Division C · Seven Lakes Invitational · 2026

143 questions · 238 points · 50 min· 68 questions from the original omitted

• This test is a class set. Please do not write any answers on this paper. • Please write all answers clearly; illegible answers will not be scored. • Sig figs won't be graded. However, it's good practice to use at least 3. • Try to use units; no answers without units will be assumed to be SI. • There is no penalty for wrong answers. Answer every question, even if you aren't sure if you're correct. • Good luck on the test!

MCQ (54)

Question 1

1 pt

How many grams of products are formed when 10.0 mL of 0.0015 M KCl is mixed with 12.45 mL of 3.45 M CaS?

A. 4.45 g of productsB. 0.94 g of productsC. 0.034 g of productsD. none of the above

Question 2

1 pt

4 g of HCl is mixed with 100 g of water. How many grams of NaOH will be needed to neutralize this solution if the volume remains the same?

A. 4.39 gB. 4.00 gC. 3.28 gD. 1.09 g

Question 3

1 pt

A molecule composed of only C, H, and O is 68.51% carbon and 8.65% hydrogen by mass. What is the empirical formula of the molecule?

A. C₄H₅O₃B. C₂H₇O₃C. C₄H₆OD. C₃H₄O

Question 4

1 pt

A hydrocarbon is combusted so that 0.918 L of H₂O is produced at 298 K and 1.05 atm. What was the total mass of hydrogen in the hydrocarbon?

A. 0.71 gB. 0.079 gC. 0.04 gD. 0.96 g

Question 5

1 pt

An aqueous solution is composed of 28.3% w/w of an unknown solute. What is the identity of the solute if the ending solution has a concentration of 4.52 M? The solution's density is 1007 g/L.

A. NaOHB. NaNO₃C. NaClD. HNO₃

Question 6

1 pt

If 5 g of KCl is reacted with 5 g of AgF, how much precipitate, in grams, is produced?

A. 5.65 gB. 4.18 gC. 9.61 gD. 7.53 g

Question 7

1 pt

What is the concentration of an aqueous 8% w/w NaCl solution? The solution's density is 1002 g/L.

A. 1.37 MB. 2.18 MC. 1.05 MD. 2.09 M

Question 8

1 pt

0.97 L of H₂ is collected at standard conditions after excess HCl was reacted with magnesium metal. What was the mass of the magnesium metal in grams?

A. 0.98 gB. 1.13 gC. 1.05 gD. 0.74 g

Question 9

1 pt

What will be the coefficient in front of H₂O of the following redox reaction when it is fully balanced?

OH⁻ + S₈ → S²⁻ + S₂O₃²⁻ + H₂O

A. 3B. 4C. 5D. 6

Question 10

1 pt

What is the coefficient in front of O₂ when the following equation is fully balanced?

CH₃SH + O₂ → CO₂ + H₂O + SO₂

A. 1B. 2C. 3D. 4

Question 11

1 pt

How many alpha and beta particles, respectively, are released by the decay of U-238 into Th-230?

A. 1,0B. 1,1C. 4,5D. 2,2

Question 12

1 pt

Why are the π₂p bonding orbitals in diatomic molecules with Z_avg < 8 lower in energy than the σ₂p bonding orbital?

A. The s and p orbitals mix, destabilizing the σ₂p in comparison to the π₂p orbitals.B. Empty π₂p orbitals allow for backbonding, lowering the energy of the p orbitals.C. Lack of hybridization allows for strong chelating ligands to cause σ₂p expansion.D. The small size of these molecules means that relativistic effects have to be accounted for in the σ₂p orbital.

Question 13

1 pt

For the following reaction, identify the reducing agent.

2Cu²⁺ + 4I⁻ → 2CuI + I₂

A. Cu²⁺B. I⁻C. CuID. I₂

Question 14

1 pt

For the following reaction, identify the oxidizing agent.

CH₄ + 2O₂ → CO₂ + 2H₂O

A. H₂OB. CO₂C. O₂D. CH₄

Question 15

1 pt

Which of the following reactions cannot be a redox reaction?

A. NeutralizationB. SynthesisC. DecompositionD. Combustion

Question 16

1 pt

What are the products of the reaction between hydrochloric acid and sodium thiosulfate?

A. H₂O, NaCl, H₂S₂O₃B. NaCl, H₂SO₄, SC. H₂S₂O₃, NaClD. S, SO₂, NaCl, H₂O

Question 17

1 pt

What is the sum of the coefficients of the following reaction when it is fully balanced?

Cr₂O₇²⁻ + H⁺ + C₂O₄²⁻ → Cr³⁺ + CO₂ + H₂O

A. 29B. 31C. 30D. 33

Question 18

1 pt

What is the coefficient in front of H₂O when the following equation is fully balanced?

H₂O₂ + I⁻ + H⁺ → I₂ + H₂O

A. 1B. 2C. 3D. 4

Question 19

1 pt · select all that apply

What are the products of the reaction between silver nitrate and potassium carbonate? [select all that apply]

A. Ag₂CO₃B. CO₂C. KNO₃D. NO₂

Question 20

1 pt

Which of the following are correct products formed from the combustion of C₂H₆S?

I. CO₂ II. SO₃ III. H₂S

A. I and II onlyB. I and III onlyC. III onlyD. I only

Question 21

1 pt

If iron reacts with zinc chloride, what are the products of the reaction?

A. FCl₂ and ZnB. FeCl₃ and ZnC. Fe₂O₃ and ZnCl₂D. No reaction

Question 22

1 pt

What is the chemical formula for tetrachloroaurate (II)?

A. AgCl₂B. [AuCl₄]²⁻C. AuCl₄D. [AgCl₂]²⁺

Question 23

1 pt

Which of the following is true about O₂?

A. It is ferromagneticB. It is diamagneticC. It is paramagneticD. It is ferrimagnetic

Question 24

1 pt

What is the oxidation number of a gallium atom with the following electron configuration?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰

A. +1B. +2C. +3D. +4

Question 25

1 pt

Which of the following compounds are written correctly?

I. Tin fluoride, SnF₂ II. Potassium carbonate KCO₃ III. Sulfurous acid, H₂SO₃

A. III onlyB. I and II onlyC. I, II, and IIID. none of the above

Question 26

1 pt

Which of the following molecules are paramagnetic?

A. H₂B. NO₂C. H₂OD. NaCl

Question 27

1 pt · select all that apply

Which of these species are insoluble in water?

A. ZrSiO₄B. AlPC. AgNO₃D. Au

Question 28

1 pt

A strip of nickel metal is immersed in an aqueous solution of silver nitrate. After several minutes, metallic silver forms on the strip. Which statement best explains the driving force of this reaction?

A. Nickel reduces Ag⁺ because Ag⁺ has a more positive reduction potential than Ni²⁺B. Silver oxidizes Ni²⁺ because Ni²⁺ has a more positive reduction potential than Ag⁺C. Nickel and silver form an intermetallic compound that is energetically favoredD. The reaction is driven by the release of ammonia from hydrolyzed silver nitrate

Question 29

1 pt

When solid aluminum carbide (Al₄C₃) is added to water, a colorless gas evolves. Which reaction product best accounts for this observation?

A. Methane from the hydrolysis of carbide ionsB. Ethane from the reduction of water by aluminumC. Carbon monoxide from the disproportionation of carbonD. Hydrogen gas from aluminum reacting directly with water

Question 30

1 pt

If the rate constant of a reaction is 0.0018 s⁻¹ at 32 ºC, and the activation energy is 60 kJ/mol, find the value of the rate constant at 40 ºC.

A. 1.0 × 10⁻³ s⁻¹B. 1.9 × 10⁻³ s⁻¹C. 2.3 × 10⁻³ s⁻¹D. 3.4 × 10⁻³ s⁻¹

Question 31

1 pt

What is the activation energy of a reaction at 11 K with a pre-exponential factor of 43 M⁻¹ s⁻¹ and a rate constant of 26 M⁻¹ s⁻¹?

A. 38.03 J/molB. 46.01 J/molC. 55.01 J/molD. 66.56 J/mol

Question 32

1 pt

Bessie the Chemistry cow has a mysterious substance with a rate constant of 1.66 × 10⁻² s⁻¹ at a temperature of 650K, and an activation energy of 112.3 kJ/mol. However, part of her notebook is blurred, and the temperature that resulted in a rate constant of 1.89 × 10⁻³ s⁻¹ is unreadable. Help her find the temperature.

A. 588.5 KB. 654.3 KC. 596.8 KD. 473.6 K

Question 33

1 pt

Consider the following reversible reaction at 298K.

A ⇌ B

The pre-exponential factor for the forward and reverse reaction is 1.50 × 10¹³ s⁻¹ and 2.20 × 10¹² s⁻¹, respectively. The activation energies for the forward and reverse reactions are 85 J/mol and 120 J/mol, respectively. Find the equilibrium constant K of the reaction.

A. 8.317B. 6.913C. 9.314D. 7.002

Question 34

1 pt

A reaction at 298 K has a rate constant of 3.28 × 10⁻⁶ M⁻¹ s⁻¹. If the activation energy of this reaction is 107 kJ/mol, what is the pre-exponential factor and its correct units?

A. 1.87 × 10¹³ s⁻¹B. 2.314 × 10¹² M⁻¹ s⁻¹C. 1.87 × 10¹³ M⁻¹ s⁻¹D. 2.314 × 10¹³ s⁻¹

Question 35

1 pt

If you double the concentration of the reactant of a unimolecular second-order reaction, what will be the rate law in terms of the rate for a unimolecular first-order reaction (R)?

A. ½ RB. 2RC. 4RD. ¼ R

Question 36

1 pt

Determine the rate law for the reaction below.

Trial	[A] (M)	[B] (M)	Rate (M/s)
1	0.15	0.20	1.0 × 10⁻⁴
2	0.15	0.60	9.0 × 10⁻⁴
3	0.30	0.60	1.8 × 10⁻³

A. k[A][B]B. k[A]³[B]C. k[A][B]²D. k[A][B]³

Question 37

1 pt

Consider the following table for a reaction. The rate law for the reaction is Rate = k[A]²[B]. What would best fit in the blank for Trial 2?

Trial	[A] (M)	[B] (M)	Rate (M/s)
1	1.0	1.0	1.0
2	?	1.0	4.0
3	1.0	2.0	2.0

A. 4.0 MB. 2.0 MC. 3.0 MD. 1.0 M

Question 42

1 pt

In a hypothetical situation where the order of the reaction A + B → C is -1 with respect to [A], what does this negative reaction order mean?

A. As the concentration of A increases, the rate of reaction will not be affectedB. As the concentration of A decreases, the rate of reaction will decrease by 1/[A]C. As the concentration of A increases, the rate of the reaction will decrease by 1/[A]D. As the concentration of A increases, the rate of reaction will decrease linearly

Question 38

1 pt

NO₂ + F₂ → NO₂F + F (slow) F + NO₂ → NO₂F (fast)

What is the overall rate law for the reaction?

A. k₂[F]²[NO₂]²B. k₁[F₂][NO₂]²C. k₂[F][NO₂]D. k₁[NO₂][F₂]

Question 39

1 pt

Given the following reaction: 2 A + 3 B → 4 C + D

Which of the following is incorrect?

A. The rate of disappearance of A is half the rate of appearance of CB. The rate of appearance of D is half the rate of disappearance of AC. The rate of appearance of D is three times the rate of disappearance of BD. None of the above

Question 40

1 pt

Consider the following: ? (fast) NO₂Cl + Cl → NO₂ + Cl₂ (slow)

If the rate law of the overall reaction is Rate = k[NO₂Cl]²[NO₂]⁻¹, what could be the missing reaction?

A. N₂ + O₂ → N₂O₂B. NO₂Cl → NO₂ + ClC. Cl + NO₂ → NO₂ClD. NO₂ + Cl₂ → Cl + NO₂Cl

Question 41

1 pt

For the following reaction, 2 O₃ → 3 O₂

What is the reaction order with respect to O₂?

A. 3/2B. 2C. 3D. cannot be determined

Question 43

1 pt

How is the efficiency of a catalyst measured?

A. Via the turnover frequencyB. Via the catalytic capacityC. Via their reaction orderD. Via the Arrhenius equation

Question 44

1 pt

What is the function of a catalyst?

A. It increases the amount of reactants to speed up the reactionB. It introduces a new reaction pathway that requires lower activation energy to speed up the reactionC. It increases the temperature to speed up the reactionD. It increases the collision frequency between reactants to speed up the reaction

Question 45

1 pt

What are the units of the rate constant of a 4th-order reaction?

A. M⁻² s⁻¹B. M⁻² s⁻²C. M⁻³ s⁻¹D. M⁻⁴ s⁻²

Question 46

1 pt

If the order of reaction with respect to [B] is 0th order, what is the missing initial rate?

Trial	[A]	[B]	Rate (M/s)
1	0.25	0.60	2.78
2	0.50	0.30
3	0.50	0.60	5.56

A. 2.78B. 1.39C. 5.56D. 4.17

Question 47

1 pt

Given the following data and the reaction AB → A + B, what is the rate of the reaction?

Time (s)	[AB]
0	0.800 M
5	0.372 M
10	0.173 M
15	0.081 M

A. First order, the plot of [A] vs. time is linearB. Second order, the plot of ln[A] vs. time is linearC. First order, the plot of ln[A] vs. time is linearD. Second order, the plot of [A] vs. time is linear

Question 48

1 pt

A reaction has a rate constant of k = 0.25 M⁻¹ s⁻¹. If the initial concentration of the reactant, A, is 2.0 M, what will be the concentration of A after 4 seconds?

A. 1.0 MB. 0.67 MC. 0.33 MD. 0.25 M

Question 49

1 pt

In a 0th order reaction, [Y]₀ is 0.113 M and the rate constant is 0.03 M/s. After 2.9 seconds, what concentration of Y has been depleted?

A. 0.087 MB. 0.034 MC. 0.046 MD. 0.079 M

Question 50

1 pt

Given a zero-order reaction that starts with 1.0 M and has a rate constant of 0.050 M/s, what is the time required for the concentration to go from 0.60 M to 0.20 M?

A. 4 secondsB. 8 secondsC. 12 secondsD. 16 seconds

Question 51

1 pt

The decomposition of molecule X is second order. If [X]₀ is 0.193 M with a rate constant of 1.53 × 10⁻³ M⁻¹ s⁻¹, what is the half-life?

A. 3.39 × 10³ sB. 2.18 × 10³ sC. 453.04 sD. 127.02 s

Question 52

1 pt

Consider the 2nd order reaction A + B → C. When [B]₀ >> [A]₀, the half-life of the pseudo-first-order reaction is 93.4 s. If [B] is 2.07 × 10⁻⁶ M, what is the rate constant k of the reaction in M⁻¹ s⁻¹?

A. 7.42 × 10⁻³B. 3.16 × 10²C. 1.13 × 10⁻²D. 3.59 × 10³

Question 53

1 pt

What is the reaction order if the time required for 100% completion is 2 times the first half-life?

A. Zero orderB. First orderC. Second orderD. Third order

Question 54

1 pt

The decomposition NO₂ → 2 NO + O₂ occurs in the following mechanism: NO₂ + NO₂ → N₂O₄ (fast equilibrium) N₂O₄ → NO + NO₃ (fast) NO₃ + NO₂ → 2 NO₂ + O₂ (slow)

Which of the following is the rate law for this mechanism?

A. Rate = k[NO₂]B. Rate = k[NO₂]²C. Rate = k[NO₂]³D. Rate = k[NO₃][NO₂]

STOICHIOMETRY AND REACTIONS FRQ (46)

Question 1a

1 pt

Write the complete ionic equation of the following reaction, including state symbols (assume the reaction goes to completion).

A saturated solution of barium hydroxide is mixed with a solution of iron (III) sulfate.

Question 1d

3 pts

Given 1 mol of each reactant (Ba(OH)₂, Fe₂(SO₄)₃, HF) in the previous reactions, which of the reactions would produce the greatest mass of products? What is the total mass of the products combined? (For aqueous solutions, use 1 L of 1 M)

PassageFor questions 2a, 2b, 2c, 2e

You have 100 g of a mystery compound that contains 81.8% carbon, 6.1% hydrogen, and 12.1% oxygen. Show work for each of the questions.

Question 2a

2 pts

Write the empirical formula for the compound.

Question 2b

1 pt

Using the formula, calculate the number of moles of hydrogen in 150 g of the compound.

Question 2c

1 pt

Write the fully balanced chemical reaction for when this mystery substance is combusted. Do not include states.

Question 2e

1 pt

What is the common name for this compound?

Question 3a

4 pts

Balance the following redox reaction in basic conditions.

PtO₄²⁻ + Be → BeO₃²⁻ + Pt(OH)₆²⁻

Question 3b

4 pts

Balance the following redox reaction in basic conditions.

Bi³⁺ + MnO₄⁻ → MnO₂ + BiO₃⁻

Question 4a

4 pts

Balance the following redox reaction in acidic conditions.

Cr₂O₇²⁻ + Fe²⁺ → Cr³⁺ + Fe³⁺

Question 4b

4 pts

Balance the following redox reaction in acidic conditions.

MnO₄⁻ + C₂O₄²⁻ → Mn²⁺ + CO₂

KINETICS FRQ (36)

Question 5a

1 pt

Predict the outcome of the following reaction. No need to balance or include states.

Permanganate ions react with hydrogen peroxide in neutral conditions.

Question 5b

1 pt

Predict the outcome of the following reaction. No need to balance or include states.

Sulfide gas reacts with nitrate ions in acidic conditions to form elemental sulfur and nitrogen monoxide gas.

Question 5c

1 pt

Predict the outcome of the following reaction. No need to balance or include states.

Ammonium chloride reacts with calcium hydroxide upon heating.

Question 5d

1 pt

Predict the outcome of the following reaction. No need to balance or include states.

Bromine gas bubbled into basic solution.

PassageFor questions 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Question 6a

1 pt

A solution of potassium phosphate is mixed with a solution of barium nitrate.

Reaction type: ____ Products: ____

Question 6b

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Solid calcium metal is placed into a solution of copper chloride.

Reaction type: ____ Products: ____

Question 6c

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Magnesium and Copper Sulfate in aqueous solution.

Reaction type: ____ Products: ____

Question 6d

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Potassium bromide and chlorine gas.

Reaction type: ____ Products: ____

Question 6e

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Silver nitrate and sodium chloride in aqueous solution.

Reaction type: ____ Products: ____

Question 6f

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Methane burns in oxygen gas.

Reaction type: ____ Products: ____

Question 6g

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Silver nitrate reacts with potassium chloride in an aqueous solution.

Reaction type: ____ Products: ____

Question 6h

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Calcium carbonate decomposes when heated.

Reaction type: ____ Products: ____

Question 6i

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Aluminum metal reacts with oxygen gas.

Reaction type: ____ Products: ____

Question 6j

1 pt

For the following reaction, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Sodium hydroxide reacts with hydrochloric acid.

Reaction type: ____ Products: ____

PassageFor questions 1a, 1b, 1c, 1a

Below are the reaction steps to the Free-Radical Chlorination of Methane. Assume that all steps before the Termination steps are rapid reactions.

Initiation:

Step 1: Cl₂ → 2 Cl· (k₁)

Propagation:

Step 2: Cl· + CH₄ → HCl + CH₃· (k₂)

Step 3: CH₃· + Cl₂ → CH₃Cl + Cl· (k₃)

Termination:

Step 4: Cl· + Cl· → Cl₂ (k₄)

Step 5: CH₃· + Cl· → CH₃Cl (k₅)

Step 6: CH₃· + CH₃· → C₂H₆ (k₆)

Question 1a

2 pts

Derive an equation that equates the rate of formation and consumption of intermediate Cl· (hint: propagation steps can be neglected).

Question 1b

2 pts

Derive an equation that equates the rate of formation and consumption of intermediate CH₃·.

Question 1c

1 pt

Derive an equation that equates the rate of formation and consumption of intermediate Cl₂.

PassageFor questions 3a, 3b, 3c, 3d, 3a

A couple of SLHS students conducted an experiment investigating the decomposition of nitrogen dioxide at different temperatures. When they graphed their data on a plot of ln k versus 1/T, it produced a straight line. The table below shows the output of two rate constants for two different temperatures of the reaction. Assume R = 8.314 J mol⁻¹ K⁻¹.

Temperature	Rate Constant
400 ºC	2.5 × 10⁻³ s⁻¹
450 ºC	4.15 × 10⁻² s⁻¹

Question 3a

2 pts

What is the activation energy of this reaction? (Express your answer in kJ·mol⁻¹)

Question 3b

2 pts

Calculate the pre-exponential factor A in s⁻¹, using your answer from part a.

Question 3c

3 pts

If the students were to run another experiment at 475 ºC, what is the predicted value of the rate constant, and how does it compare to the rate constant at 400 ºC?

Question 3d

2 pts

Does the value for the rate constant of the second experiment make sense, or was there an error in the experiment? Explain.

LAB (67)

PassageFor questions L2a, L2b, L3, L2a, L2b, L3

For this lab, you will determine the reaction order of NaOH with respect to Ca(NO₃)₂. Since we cannot accurately calculate the reaction rates with the equipment we have, we will approximate them with reaction time.

Materials:

10–100 mL graduated cylinder
32 mL of 0.6 M Ca(NO₃)₂
20 mL of 1 M NaOH
50 mL beaker
Timer
Maybe one extra beaker

PassageFor questions 4a, 4b, 4c, 4d, 4e

This equation represents the iodination of acetone in an acidic aqueous solution:

CH₃COCH₃(aq) + I₂(aq) + H⁺ → CH₃COCH₂I(aq) + HI(aq)

The initial concentration of catalyst [H⁺] is 1.00 M and remains constant. The following initial rate data were collected:

Trial	[CH₃COCH₃] (M)	[H⁺] (M)	[I₂] (M)	Initial Rate (M/s)
1	0.1	0.1	0.01	1.36 × 10⁻³
2	0.2	0.1	0.01	2.72 × 10⁻³
3	0.1	0.2	0.01	2.72 × 10⁻³
4	0.1	0.1	0.02	1.36 × 10⁻³
5	0.2	0.2	0.02	5.44 × 10⁻³
6	0.1	0.1	0.001	1.36 × 10⁻³

Question 4a

2 pts

Write the complete rate law for the reaction.

Question 4b

1 pt

Under what condition would this reaction be pseudo-first order?

Question 4c

1 pt

Calculate the rate constant of this reaction.

Question 4d

1 pt

Considering that [H⁺]₀ ≫ [CH₃COCH₃]₀, write the new rate law in terms of [CH₃COCH₃] and the pseudo rate constant k′.

Question 4e

7 pts

The reaction begins with 2.15 × 10⁻³ M CH₃COCH₃. Still assuming pseudo-first order, at 19.3 seconds, [CH₃COCH₃] = 4.35 × 10⁻⁴ M. What is [H⁺] at this time?

Question L2a

2 pts

Pre-lab question 2. Each person will be given a total of 20 mL of 1M NaOH.

(a) If a person were to divide 20 mL of [NaOH]₀ evenly across 4 trials, how much NaOH (in mL) should each trial use?

Question L2b

16 pts

Pre-lab question 2. Each person will be given a total of 20 mL of 1M NaOH.

(b) Using the amount of evenly divided NaOH (in mL) you calculated in part a, determine the amount of H₂O that should be added to each divided portion of [NaOH]ᵢ to obtain the [NaOH]f listed in table 1. Your answer should be written in Table 1 to one decimal place.

Question L3

2 pts

Pre-lab question 3. Each person will be given a total of 32 mL of Ca(NO₃)₂. If a person were to divide the 32 mL of Ca(NO₃)₂ evenly across 4 trials, how much Ca(NO₃)₂ (in mL) will be used per trial?

PassageFor questions P1a, P1b, P1c, P1d

Post-Lab Question 1. (16 points) The equation log(rate₁/rate₂) / log([A]₀,₁/[A]₀,₂) can be used to calculate n, the reaction order, where [A]₀,₁ corresponds to the concentration of a species used to obtain rate 1. Calculate your answer to the 3rd decimal place.

Question P1a

4 pts

Use the given equation to calculate the reaction order between runs 1 and 2. Show work.

Question P1b

4 pts

Use the given equation to calculate the reaction order between runs 2 and 3. Show Work.

Question P1c

4 pts

Use the given equation to calculate the reaction order between runs 3 and 4. Show Work.

Question P1d

4 pts

What is the average reaction order across all the runs?

Question P2

1 pt

Post-Lab Question 2. Name one way we can change the experiment setup so the reaction time speeds up.

Question P3

2 pts

Post-Lab Question 3. Write the balanced net ionic reaction between NaOH and Ca(NO₃)₂. Include states.

Question 15

1 pt

Which of the following reactions can not be a redox reaction?

A. NeutralizationB. SynthesisC. DecompositionD. Combustion

Question 31

1 pt

What is the activation energy of a reaction at 11 K with a pre-exponential factor of 43 M⁻¹s⁻¹ and a rate constant of 26 M⁻¹s⁻¹?

A. 38.03 J/molB. 46.01 J/molC. 55.01 J/molD. 66.56 J/mol

Question 32

1 pt

Bessie the Chemistry cow has a mysterious substance with a rate constant of 1.66 × 10⁻² s⁻¹ at a temperature of 650 K, and an activation energy of 112.3 kJ/mol. However, part of her notebook is blurred, and the temperature that resulted in a rate constant of 1.89 × 10⁻³ s⁻¹ is unreadable. Help her find the temperature.

A. 588.5 KB. 654.3 KC. 596.8 KD. 473.6 K

Question 33

1 pt

Consider the following reversible reaction at 298 K.

A ⇌ B

A. 8.317B. 6.913C. 9.314D. 7.002

Question 45

1 pt

What are the units of the rate constant of a 4th-order reaction?

A. M⁻²s⁻¹B. M⁻²s⁻²C. M⁻³s⁻¹D. M⁻⁴s⁻²

Question 46

1 pt

If the order of reaction with respect to [B] is 0th order, what is the missing initial rate?

Trial	[A]	[B]	Rate (M/s)
1	0.25	0.60	2.78
2	0.50	0.30	5.56
3	0.50	0.60	?

A. 2.78B. 1.39C. 5.56D. 4.17

Question 48

1 pt

A reaction has a rate constant of k = 0.25 M⁻¹s⁻¹. If the initial concentration of the reactant, A, is 2.0 M, what will be the concentration of A after 4 seconds?

A. 1.0 MB. 0.67 MC. 0.33 MD. 0.25 M

STOICHIOMETRY AND REACTIONS FRQ (46)

Question 1a

1 pt

Write the complete ionic equation of the following reaction, including state symbols (Assume every reaction goes to completion).

A saturated solution of barium hydroxide is mixed with a solution of iron (III) sulfate.

Question 1b

1 pt

Write the complete ionic equation of the following reaction, including state symbols (Assume every reaction goes to completion).

Solutions of ammonia and hydrofluoric acid are mixed together.

Question 1c

1 pt

Write the complete ionic equation of the following reaction, including state symbols (Assume every reaction goes to completion).

Hydrogen sulfide gas is bubbled through a solution of potassium hydroxide.

PassageFor questions 2b, 2c

You have 100 g of a mystery compound that contains 81.8% carbon, 6.1% hydrogen, and 12.1% oxygen. Show work for each of the questions.

Question 2b

1 pt

You have 100 g of a mystery compound that contains 81.8% carbon, 6.1% hydrogen, and 12.1% oxygen. Show work for each of the questions.

Using the formula, calculate the number of moles of hydrogen in 150 g of the compound.

Question 2c

1 pt

You have 100 g of a mystery compound that contains 81.8% carbon, 6.1% hydrogen, and 12.1% oxygen. Show work for each of the questions.

Write the fully balanced chemical reaction for when this mystery substance is combusted. Do not include states.

PassageFor questions 5a, 5b, 5c, 5d, 5e, 5f, 5g

Predict the outcomes of the following reactions. No need to balance or include states.

Question 5a

1 pt

Permanganate ions react with hydrogen peroxide in neutral conditions.

Question 5b

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Sulfide gas reacts with nitrate ions in acidic conditions to form elemental sulfur and nitrogen monoxide gas.

Question 5c

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Ammonium chloride reacts with calcium hydroxide upon heating.

Question 5d

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Bromine gas bubbled into basic solution.

Question 5e

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Combustion of ethyl thiol (C₂H₅SH) in excess oxygen.

Question 5f

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Combustion of glycine (NH₂CH₂COOH).

Question 5g

1 pt

Predict the outcomes of the following reactions. No need to balance or include states.

Neutralization of hypochlorous acid and ammonia.

PassageFor questions 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Question 6a

1 pt

A solution of potassium phosphate is mixed with a solution of barium nitrate.

Question 6b

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Solid calcium metal is placed into a solution of copper chloride.

Question 6c

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Magnesium and Copper Sulfate in aqueous solution.

Question 6d

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Potassium bromide and chlorine gas.

Question 6e

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Silver nitrate and sodium chloride in aqueous solution.

Question 6f

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Methane burns in oxygen gas.

Question 6g

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Silver nitrate reacts with potassium chloride in an aqueous solution.

Question 6h

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Calcium carbonate decomposes when heated.

Question 6i

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Aluminum metal reacts with oxygen gas.

Question 6j

1 pt

For each of the following reactions, write the products and identify the type of reaction. It is not necessary to balance the reactions, but include states.

Sodium hydroxide reacts with hydrochloric acid.

KINETICS FRQ (36)

Question 1a

2 pts

Derive an equation that equates the rate of formation and consumption of intermediate Cl· (hint: propagation steps can be neglected).

Question 3a

2 pts

What is the activation energy of this reaction? (Express your answer in kJ·mol⁻¹)

Question 4

2 pts

This equation represents the iodination of acetone in an acidic aqueous solution: CH₃COCH₃(aq) + I₂(aq) + H⁺ → CH₃COCH₂I(aq) + HI(aq)

The initial concentration of catalyst [H⁺] is 1.00 M and remains constant. The following initial rate data were collected:

Trial	[CH₃COCH₃] (M)	[H⁺] (M)	[I₂] (M)	Initial Rate (M/s)
1	0.1	0.1	0.01	1.36 × 10⁻³
2	0.2	0.1	0.01	2.72 × 10⁻³
3	0.1	0.2	0.01	2.72 × 10⁻³
4	0.1	0.1	0.02	1.36 × 10⁻³
5	0.2	0.2	0.02	5.44 × 10⁻³
6	0.1	0.1	0.001	1.36 × 10⁻³

(a) Write the complete rate law for the reaction.

Question 4b

1 pt

Under what condition would this reaction be pseudo-first order?

Question 4c

1 pt

Calculate the rate constant of this reaction.

Question 4d

1 pt

Considering that [H⁺]₀ ≫ [CH₃COCH₃]₀, write the new rate law in terms of [CH₃COCH₃] and the pseudo rate constant k′.

Question 4e

7 pts

The reaction begins with 2.15 × 10⁻³ M CH₃COCH₃. Still assuming pseudo-first order, at 19.3 seconds, [CH₃COCH₃] = 4.35 × 10⁻⁴ M. What is [H⁺] at this time?

Question L2a

2 pts

Each person will be given a total of 20 mL of 1M NaOH. If a person were to divide 20 mL of [NaOH]₀ evenly across 4 trials, how much NaOH (in mL) should each trial use?

Question L2b

16 pts

Each person will be given a total of 20 mL of 1M NaOH.

Using the amount of evenly divided NaOH (in mL) you calculated in part a, determine the amount of H₂O that should be added to each divided portion of [NaOH]ᵢ to obtain the [NaOH]f listed in table 1. Your answer should be written in Table 1 to one decimal place.

Question L3

2 pts

Each person will be given a total of 32 mL of Ca(NO₃)₂. If a person were to divide the 32 mL of Ca(NO₃)₂ evenly across 4 trials, how much Ca(NO₃)₂ (in mL) will be used per trial?

PassageFor questions PL1b, PL1c, PL1d

The equation log(rate₁/rate₂) / log([A]₀,₁/[A]₀,₂) can be used to calculate n, the reaction order, where [A]₀,₁ corresponds to the concentration of a species used to obtain rate₁. Calculate your answer to the 3rd decimal place.

Question PL1b

4 pts

Use the given equation to calculate the reaction order between runs 2 and 3. Show work.

Question PL1c

4 pts

Use the given equation to calculate the reaction order between runs 3 and 4. Show work.

Question PL1d

4 pts

What is the average reaction order across all the runs?

Question PL2

1 pt

Name one way we can change the experiment setup so the reaction time speeds up.

Question PL3

2 pts

Write the balanced net ionic reaction between NaOH and Ca(NO₃)₂. Include states.