5 Steps to a 5 AP Chemistry

3.A solution is prepared by mixing 50.0 mL of

0.20 M arsenic acid, H 3 AsO 4 , and 50.0 mL of

0.20 M sodium hydroxide, NaOH. Which

anion is present in the highest concentration?

(A) HAsO 42 −

(B) OH−

(C) H 2 AsO 4 −

(D) Na+

(E) AsO 33 −

4.14 H++6 Fe^2 ++Cr 2 O 72 −→ 2 Cr^3 ++6 Fe^3 +

+7 H 2 O

This reaction is used in the titration of an iron

solution. What is the concentration of the iron

solution if it takes 45.20 mL of 0.1000 M

Cr 2 O 72 −solution to titrate 50.00 mL of an acid-

ified iron solution?

(A) 0.5424 M

(B) 0.1000 M

(C) 1.085 M

(D) 0.4520 M

(E) 0.2712 M

5.Tungsten metal may be prepared by reducing

WO 3 with H 2 gas. How many grams of tungsten

may be prepared from 0.0500 mol of WO 3 with

excess hydrogen?

(A) 5.58 g

(B) 0.500 g

(C) 9.19 g

(D) 184 g

(E) 18.4 g

6.Manganese, Mn, forms a number of oxides.

A particular oxide is 63.2% Mn. What is the

simplest formula for this oxide?

(A) MnO

(B) Mn 2 O 3

(C) Mn 3 O 4

(D) MnO 2

(E) Mn 2 O 7

7.Vanadium forms a number of oxides. In which

of the following oxides is the vanadium-

to-oxygen mass ratio 2.39:1.00?

(A) VO

(B) V 2 O 3

(C) V 3 O 4

(D) VO 2

(E) V 2 O 5

8.How many grams of nitrogen are in 25.0 g of

(NH 4 ) 2 SO 4?

(A) 5.30 g

(B) 1.30 g

(C) 0.190 g

(D) 2.65 g

(E) 14.0 g

9.Nitrogen forms a number of oxides. Which of

the following oxides is 64% nitrogen?

(A) N 2 O 5

(B) N 2 O 4

(C) N 2 O 3

(D) N 2 O 2

(E) N 2 O

10.Sodium sulfate forms a number of hydrates.

A sample of a hydrate is heated until all the water

is removed. What is the formula of the original

hydrate if it loses 43% of its mass when heated?

(A) Na 2 SO 4 ·H 2 O

(B) Na 2 SO 4 ·2H 2 O

(C) Na 2 SO 4 ·6H 2 O

(D) Na 2 SO 4 ·8H 2 O

(E) Na 2 SO 4 ·10H 2 O

11.3Cu(s) +8HNO 3 (aq) → 3Cu(NO 3 ) 2 (aq)

+2 NO(g) +4 H 2 O(l)

Copper metal reacts with nitric acid according to

the above equation. A 0.30-mol sample of

copper metal and 10.0 mL of 12 M nitric acid

are mixed in a flask. How many moles of NO gas

will form?

(A) 0.060 mol

(B) 0.030 mol

(C) 0.010 mol

(D) 0.20 mol

(E) 0.10 mol

12.Gold(III) oxide, Au 2 O 3 , can be decomposed to

gold metal, Au, plus oxygen gas, O 2. How many

moles of oxygen gas will form when 221 g of

solid gold(III) oxide is decomposed? The formula

mass of gold(III) oxide is 442.

(A) 0.250 mol

(B) 0.500 mol

(C) 1.50 mol

(D) 1.00 mol

(E) 0.750 mol

96  STEP 4. Review the Knowledge You Need to Score High