AP Chemistry

Which species are considered to be Brønsted-Lowry acids?

• Only HF is a Brønsted-Lowry acid because it donates a proton

• HF and H₃O⁺ are both Brønsted-Lowry acids because they both donate protons.

• HF and F^- are both Brønsted-Lowry acids because HF gains a proton while F^- donates a proton.

• HF and are both Brønsted-Lowry acids because HF donates a proton while H₂O gains a proton.

A student titrated 100.0 mL of 0.200 M HNO₂ with 0.200 M KOH. Calculate the PH at the equivalence point.

K_a for HNO₂ = 4.0 x 10-4

Round to the nearest tenth.

When a sample of an unknown element is vaporized and injected into a mass spectrometer, the results shown below are obtained. Use these data to estimate the average atomic mass of this element.

• 117 amu

• between 117 and 118 amu

• between 118 and 119 amu

• between 119 and 120 amu

A clean strip of copper metal is massed and attached to a metal hook, suspended from a rubber stopper. The rubber stopper is placed into a very large test tube containing solid iodine, and the test tube is sealed. Iodine vapor is generated by gentle heating of the solid iodine at the bottom of the test tube. A white compound forms on the copper strip. The rubber stopper is carefully removed, and the resulting copper strip with the white compound is massed. The white compound is washed from the surface of the metal, and the copper strip is dried completely and massed. The data table is below. What is the empirical formula for this compound?

• CuI

• CuI₂

• Cu₂I

• Cu₃I₄

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-2

• 5.03 g

• 4.41 g

• .614 g

• 10.1 g

Tags

NGSS.HS-PS1-7

Once the system reaches equilibrium at 675C, additional H₂ is added and the temperature is held constant. Which statement best describes how this affects the value of K ?

• The value of K increases because the formation of products is favored.

• The value of K decreases because the formation of reactants is favored.

• The value of K remains unchanged because the temperature remained constant.

• The value of K cannot be determined until the equilibrium concentrations are determined.

Tags

NGSS.HS-PS1-5

Which of the following combination of changes to the system at equilibrium would both result in an increase in the concentration of O₂?

• An increase in the concentration of SO₂ and an increase in the temperature

• An increase in the concentration of SO₂ and a decrease in the temperature

• An increase in the concentration of SO₃ and a decrease in the temperature

• An increase in the concentration of SO₃ and an increase in the temperature

Tags

NGSS.HS-PS1-5

Titration curves can be used to calculate an unknown

The catalyzed reaction has how many intermediates?

• 0

• 1

• 2

• 3

The graph represents an

• Exothermic Reaction

• Endothermic Reaction

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1