Chem exam 4

A solution with a pOH of 6.92 has an [OH-] of 1.2 x 10-7 M. 7.1 M. 9.2 x 10-6 M. 6.9 M. 6.8 x 10-6 M.

1.2 x 10-7 M.

What is the pH of a 0.0250 M HNO, solution? 1.602 12.398 -1.602 2.500 0.000

1.602

The degree of ionization of a strong acid is a. 100%. b. between 1% and 10%. c. between 10% and 100%. d. dependent on the concentration of the acid. e. dependent the value of K.

100%.

A cup of coffee has a hydroxide ion concentration of 1 x 10-10 M. What is the pH of this coffee? 1.0 x 10-4 7.0 4.0 -10.0 10.0

4.0

A solution with a pH of 9.50 has a pOH of 9.50. 23.5. 0.50. 19.0. 4.50.

4.50.

If K for a reaction is large, AG° is definitely negative. AG" is definitely positive. AG° is equal to zero. AS is definitely negative. None of them correct

AG° is definitely negative.

Which one of the following is strong acid? A) CH2CICOOH B) CHF2COOH C) CH2BRCOOH D) CH2ICOOH

B) CHF2COOH

Which one of the following is an example of basic salt? A) NaCI B) Nal C) KCI D) NaF E) NH4CI

D) NaF

Which of the following is the conjugate base of the dihydrogen phosphate ion, H2PO4? A. H3PO4 B. H2PO4- C. HPO4^2- D. PO4^3- E. H3O+

HPO4^2-

The equilibrium constant for the formation of hydrogen iodide from hydrogen and iodine H2(g) + I2(s) 52 HI(g) is 45.0 at a certain temperature. Which statement(s) regarding this equilibrium is/are true? I. The reaction is product favored. II.The reaction is reactant favored. III. Equilibrium lies to the right. IV. Equilibrium lies to the left, a. I and III b. I and IV c. II and III d. II and IV

I and III

Which of the following cannot be a Brønsted-Lowry base? ОH- NH4+ Н2О SH- NH3

NH4+

Which one of the following is an example of acidic salt? A) NaCl B) Nal C) KCI D) CH3COONH4 E) NH4CI

NH4CI

Which of the following occurs when products are removed from a chemical reaction in solution or the gas phase at equilibrium? a. Q increases and the equilibrium shifts to produce more products. b. Q increases and the equilibrium shifts to produce more reactants. c. Q decreases and the equilibrium shifts to produce more products. d. decreases and the equilibrium shifts to produce more reactants. e. Q is unchanged by the addition of reactants.

Q decreases and the equilibrium shifts to produce more products.

Which statement below concerning a chemical reaction at equilibrium is true? Only the forward reaction stops. Only the reverse reaction stops. Both the forward and reverse reactions stop. The rates of the forward and reverse reactions are equal.

The rates of the forward and reverse reactions are equal.

Which statement about nitrous acid and nitric acid is correct? They are both weak acids. They are both strong acids. They both have one ionizable proton. Nitrous acid has the formula HNO3 Nitric acid has the formula HNO2

They both have one ionizable proton.

Which expression defines the autoionization constant for water, Kw? a. [H3O+] [OH-] b. [H2O] [H3O+] c. [OH-] [H2O] d. [H4O2+] [O2-] e. [H2O] [H2O]

a. [H3O+] [OH-]

In the Brønsted-Lowry definition of acids and bases, an acid a. is a proton donor. b. is a proton acceptor. c.forms stable hydrogen bonds d. breaks stable hydrogen bonds e. corrodes metals.

a. is a proton donor.

Carbon dioxide in the atmosphere in rainwater often lowers the pH to 5.0-5.6. The rainwater is a. neutral. b. acidic C. basic d. gray. e. poisonous.,

acidic.

Which of the following is a strong base? a) CH3NH2 b) Ва(ОН)2 c) H2O2 d) Cr(OH)3 e) CH3COOH

b) Ва(ОН)2

When pure water autoionizes, which species are produced? a. O2-, OH-, H3O+, and H2O+ b. OH- and H3O+ c. O2- and H4O2+ d. H+ and OH- e. 2 H+ and O2-

b. OH- and H3O+

Addition of reactants to a chemical reaction in solution or gas phase at equilibrium results in a. an increase in K and a shift in equilibrium to produce more products. b. an increase in K and a shift in equilibrium to produce more reactants. c. a decrease in K and a shift in equilibrium to produce more products. d. a decrease in K and a shift in equilibrium to produce more reactants. e) no change in K and a shift in equilibrium to produce more products.

e) no change in K and a shift in equilibrium to produce more products.

In equilibrium expressions, the concentrations of pure solids and liquids have the assigned value of one. have the assigned value of zero. have constant values, c, and ci. are determined from the density and molar mass. are treated as any other solute.

have the assigned value of one.

Increasing the temperature of an endothermic reaction results in a) more products and fewer reactants. b) more reactants and fewer products. c. more reactants and products. d. fewer reactants and products. e. no change in the quantities of reactants and products.

more products and fewer reactants.

Increasing the temperature of an exothermic reaction results in more products and fewer reactants. more reactants and fewer products. more reactants and products. fewer reactants and products. no change in the quantities of reactants and products.

more reactants and fewer products.

If the reaction quotient O has a larger value than the related equilibrium constant K, the reaction is at equilibrium. the reaction will continue to make more products. the reaction will consume products and make reactants. the reaction will release heat to achieve equilibrium. the value of K will increase until it is equal to Q.

the reaction will consume products and make reactants.

If the reaction quotient Q has a smaller value than the related equilibrium constant K, the reaction is at equilibrium. the reaction will continue to make more products. the reaction will consume products and make reactants. the reaction will release heat to achieve equilibrium. the value of K will decrease until it is equal to Q.

the reaction will continue to make more products.

Which of the following is a strong acid? HCIO HCIO2 НСIO3 НСIO4 None of these is a strong acid.

НСIO4