Chapter 4 Homework Flashcards Preview

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Flashcards in Chapter 4 Homework Deck (19)
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1
Q

Mixing which of the following two solutions would yield a precipitate?

A

CuSO4 + Na2S

2
Q

Which of these acids is the weakest?

A

CH3COOH

3
Q

After titrating each of the solutions in the amounts and concentrations indicated, which of these solutions has reached the neutralization point?

A

30 mL of 0.1 M HNO3 that is titrated with 30 mL of 0.10 M NaOH.

4
Q

In a “potato clock,” a piece of zinc and a piece of copper are stuck into opposite ends of a potato. Wires from the zinc and the copper are connected to a digital clock. Enough electric current flows through this circuit to power the clock. Based on this evidence, what can you conclude about potatoes?

A

They contain electrolytes.

5
Q

If 8.1 g of potassium sulfate K2SO4 (174.26 g / mol) are dissolved in water to form 175 mL of solution, what is the molarity of potassium ions (K+ ) in the solution?

A

0.53 M

6
Q

If 5.0 g of sodium chloride NaCl (58.44 g / mol) and 8.2 g of sodium sulfate Na2SO4 (142.04 g / mol) are dissolved in water to make 200 mL of solution, what is the concentration of sodium ions (Na+ ) in the solution?

A

1.1 M

7
Q

Which of the compounds shown below is likely to be the most soluble in water?

A

H11C5OH

8
Q

Which of the following represents the net ionic equation of the combination of insoluble of aluminum hydroxide and a solution of hydrobromic acid?

A

Al(OH)3(s) + 3H+(aq) -> Al3+(aq) + 3H2O(l)

9
Q

A solution of KOH is combined with a solution of FeCl3. What is the net ionic equation of the resulting precipitation reaction?

A

Fe3+(aq) + 3OH-(aq) -> Fe(OH)3 (s)

10
Q

A solution of K2SO4 and KCl is added to a solution of Ba(NO3)2. Which of these compounds will precipitate out of this combined solution?

A

BaSO4 (s)

11
Q

When two solutions are combined, a precipitation reaction occurs as shown below.
NH4+(aq) + AG+(aq) + I-(aq) + NO3-(aq) ->
NH4+(aq) + NO3-(aq) + AgI(s)
What were the original solutions if each contained a single dissolved ionic compound?

A

a solution of AgNO3 and a solution of NH4I

12
Q

Suppose a researcher spills a small amount of strong acid in a laboratory. The addition of which of these substances would make the spill safer to clean up?

A

an excess of weak base

13
Q

You have two neutral solutions. One contains the indicator methyl red, which turns red in strongly acidic aqueous solutions but is otherwise yellow. The other contains the indicator phenol red, which turns red in strongly basic aqueous solutions but is otherwise yellow. Which of these steps would allow you to tell which solution contained which indicator?

A

Add a strong acid to both solutions.

14
Q

Suppose you titrate 25.2 mL of a 0.116 M solution of an unknown acid with 23.1 mL of a 0.253 M solution of KOH to reach the equivalence point. Which of these is the most likely formula for the unknown acid?

A

H2SO4

15
Q

You need to titrate 38.2 mL of an acetic acid solution (CH3COOH). (Acetic acid is a monoprotic acid.) You begin your titration with a 0.12 M solution of KOH. After you have added 48.5 mL of the KOH solution, however, you realize that you forgot to add an indicator and have overshot the equivalence point. To neutralize the excess base, you use a second buret to add 10.2 mL of a 0.25 M solution of HCl, which brings the titrated solution back to the equivalence point. What is the molar concentration of the original acetic acid solution?

A

0.084 M

16
Q

How many milliliters of a 0.0987 M solution of
Ce(NH4 )2(NO3 )6 will it take to titrate 26.9 mL of a 0.0745 M solution of FeSO4? (In this redox titration, Fe2+ is oxidized to Fe3+, and Ce4+ is reduced to Ce3+.)

A

20.3 mL

17
Q

MnO4− is deep purple in aqueous solution, while Mn2+ is colorless. Suppose a solution of KMnO4 is being used as a sample in a redox titration against iron(II) sulfate. What would be indicated by a sudden color change in the solution from purple to colorless?

A

The equivalence point of the redox reaction has been reached.

18
Q

You have a 5.68 g sample of a compound with the formula XCl2, where X is a metal cation. When the sample is treated with an excess of silver nitrate, 10.3 g of silver chloride (AgCl) precipitate. What is the identity of the metal cation in the sample?

A

strontium

19
Q

Suppose you have a 40.3 mL sample of a solution containing a mixture of nitric acid (HNO3 ) and hydrochloric acid (HCl). The concentration of hydrogen ions in this solution is 0.241 M. When you add an excess of silver nitrate to the solution, 0.823 g of silver chloride (AgCl) precipitate. What was the molar concentration of HNO3 in the original solution?

A

9.90 × 10^−2 M

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