(^96) › STEP 4. Review the Knowledge You Need to Score High
- 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+ - 14 H+(aq) + 6 Fe^2 +(aq) + Cr 2 O 72 - (aq) →
2 Cr^3 +(aq) + 6 Fe^3 +(aq) + 7 H 2 O(l)
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 acidi-
fied iron solution?
(A) 0.5424 M
(B) 0.1000 M
(C) 1.085 M
(D) 0.4520 M
- Which of the following best represents the bal-
anced net ionic equation for the reaction of
silver carbonate with concentrated hydrochloric
acid? Silver ions have a 1+ charge. In this reac-
tion, all silver compounds are insoluble.
(A) 2 AgCO 3 + 4 H+ + Cl- → Ag 2 Cl + 2 CO 2- 2 H 2 O
(B) Ag 2 CO 3 + 2 H+ + 2 Cl- → 2 AgCl + CO 2 - H 2 O
(C) AgCO 3 + 2 H+ → Ag+ + CO 2 + H 2 O
(D) Ag 2 CO 3 + 4 Cl- → 2 AgCl 2 + CO 32 -
- 2 H 2 O
- Vanadium forms several 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
7. A student takes a beaker containing 25.0 mL
of 0.10 M magnesium nitrate, Mg(NO 3 ) 2 , and
adds, with stirring, 25.0 mL of a 0.10 M potas-
sium hydroxide, KOH. A white precipitate of
magnesium hydroxide immediately forms. After
the reaction, the concentration of the hydroxide
ion is very low. Which of the following correctly
indicates the relative concentrations of the other
ion’s concentrations?
(A) [K+] > [Mg^2 +] > [NO 3 - ]
(B) [Mg^2 +] > [NO 3 - ] > [K+]
(C) [K+] > [NO 3 - ] > [Mg^2 +]
(D) [NO 3 - ] > [K+] > [Mg^2 +] - Sodium sulfate forms several 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 - 3 Cu(s) + 8 HNO 3 (aq) → 3 Cu(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 mole 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 mole
(B) 0.030 mole
(C) 0.010 mole
(D) 0.20 mole
- 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 for-
mula mass of gold(III) oxide is 442 g/mole.
(A) 0.250 mole
(B) 0.500 mole
(C) 0.750 mole
(D) 1.00 mole