AP Chem Finals Review (2017 + 2018 MC)

The students determined that the reaction produced 0.010 mol of Cu(NO3)2. Based on the measurement, what was the percent of Cu by mass in the original 2.00 g sample of the mixture?

32%

[concentration graph + background paragraph] If the absorbance of the mixture is 0/20 at 453 nm, how many moles of Fe3+ (aq) were present in the 100. mL sample? (Assume that any volume change due to adding the KSCN(s) is negligible.)

4 x 10^-6 mol

[ionization energy graph + background sentence] On the basis of the information given, which of the following reactions is exothermic?

Al(g) + Mg+(g) --> Al+(g) + Mg(g)

[lewis structures of reaction] In the reaction represented above, what is the hybridization of the C atoms before and after the reaction occurs?

Before: sp2 After: sp3

Which of the following has the bonds arranged in order of decreasing polarity?

H-F > N-F > F-F

[paragraph about reaction, brown gas turning things blue] Which of the following is true about this reaction?

It is a redox reaction, because Cu(s) is oxidized and the nitrogen atom in NO3-(aq) is reduced

[diagram of solid v. liquid MgO] Based on the diagram above, which of the following best helps to explain why MgO(s) is not able to conduct electricity, but MgO(l) is a good conductor of electricity?

MgO(s) consists of separate Mg2+ ions and O2- ions held in a fixed lattice, but in MgO(l) the ions are free to move and conduct electricity.

The ideal gas law best describes the properties of which of the following gases at 0 C and 1 atm?

N2

[circle molecule picture + background sentence] Which of the following best represents the contents of the box after the reaction has proceeded as completely as possible?

The box containing 4 CO2 molecules and 1 O2 molecule

[table with Cu and absorbance + paragraph] On the basis of the data provided, which of the following is a possible error that the student made?

The student labelled the cuvettes incorrectly, reversing the labels on two of the solutions of known concentrations.

In one student's experiment the reaction proceeded at a much slower rate than it did in the other students' experiments. Which of the following could explain the slower reaction rate?

The student used a 1.5 M solution of HNO3(aq) instead of a

[amu graph] The mass spectrum of an average sample of a pure element is shown in the figure above. Which of the following is the identity of the element?

Zr

At 298 K and 1 atm, Br2 is a liquid with a high vapor pressure, and Cl2 is a gas. Those observations provide evidence that under the given conditions, the

forces among Br2 molecules are stronger than those among Cl2 molecules