1.What values of x,  y andz balance the equation:

xSO_2    +   yH^+   +   Cr₂O₇^2– → 3SO₄^{2– Â} + z Cr³⁺+   H₂O ?

2.What is the stoichiometric ratio of solid phosphorus (P) tochlorine gas (Cl₂) required to give phosphorustrichloride (PCl₃)?

3.What is the mass fraction of carbon in anilineC₆H₅NH₂ expressed as apercentage?

4.

Arrange the following in order of increasing amount ofsubstance:

(i)           24 g of sodium metal
(ii)           40 g ofcarbon dioxide
(iii)          4 g ofhydrogen gas

5.What volume of 0.220 M NaOH(aq) should be used to prepare 303mL of 2.02 x 10^–3 M NaOH(aq) ?

6.

Gold hydroxide Au(OH)₃ is prepared for electroplatinggold by the following reaction

2 KAuCl₄(aq) + 3 Na₂CO₃(aq) + 3H₂O(l) → 2 Au(OH)₃(s) + 6 NaCl(aq) + 2KCl(aq) + 3 CO₂(g)

The following amounts are mixed KAuCl₄ = 2.3 mol,Na₂CO₃ = 7.0 mol and H₂O = 10L.
What is the limiting reagent, and what amount of gold hydroxide isformed if the reaction is ‘stoichiometric’? (M(H₂O) = 18 g mol^–1, ρ(H₂O) = 1.0kg L^–1)

Select one:

a. Na₂CO₃ , 1.57 mol

b. KAuCl₄ , 4.6 mol

c. KAuCl₄ , 2.3 mol

d. H₂O , 6.9 mol

e. KAuCl₄ , 6.9 mol

7.

What are the chemical formulae for the following acids: nitricacid, acetic acid, hydrochloric acid, sulfuric acid?

Select one:

a. H₂NO₃, CH₃COOH,HClO₂, H₂SO₃

b. HNO₂, CH₃COOH, HCl, HSO₃

c. HNO₃, CH₃CH₂OH, HCl,H₂SO₃

d. HNO₂, CH₃CH₂OH, HClO,H₂SO₄

e. HNO₃, CH₃COOH, HCl, H₂SO₄