Answer the questions on a separate sheet of paper bearing yo

Answer the questions on a separate sheet of paper bearing your name 1.Balance the following equations H2O(/) + Narco,(aq) HCl(aq ) NaCl(aq) + CO2(g) a) S(s) + O2(g) SO\'(g) b) + 2. Calculate the molar masses of: a) NH b) (NH so CIH.COOH d) CuSO4·5H20 c) Ca(PO) iron and the other substances: CO(g) Fe(s) CO2(g) + Fero.(s) + 4. Balance the equation below then a) calculate moles of NaOH required to react with 0.50 moles of Co. and b) the moles of Na CO, formed NaOH(aq) +COrlg) Na:CO3(aq) + H2O(T)

Solution

1. Just use Hit and Trial method

(a)

2 S (s) + 3 O₂ (g) -------------> 2 SO₃ (g)

(b)

Na₂CO₃ (aq.) + 2 HCl (aq.) -----------> 2 NaCl (aq.) + CO₂ (g) + H₂O (l)

(c)

2 C₂H₆ (g) + 7 O₂ (g) --------> 4 CO₂ (g) + 6 H₂O (g)

2.

Molar mass of a molecule = sum of the atomic masses of all the atoms that form the molecule.

(a)

NH₃ = 1 (N) + 3 (H) = 1 (7) + 3 (1) = 10 g/mol

(b)

(NH₄)₂SO₄ = 2 (N) + 8(H) + 1(S) +4(O) = 2(7) + 8(1) +1(32) + 4 (16) = 118 g/mol

(c)

CH₃COOH = 2 (C) + 2 (O) + 4 (H) = 2 (12) + 2 (16) + 4 (1) = 60 g/mol

(d)

CuSO₄.5H₂O = 1(Cu) + 1(S) + 9(O) + 10(H) = 1(63.5) + 1(32) + 9(16) + 10(1) = 249.5 g/mol

(e)

Ca₃(PO₄)₂ = 3(Ca) + 2(P) + 8(O) = 3(40) + 2(31) + 8(16) = 310 g/mol

3.

Fe₂O₃ (s) + 3 CO (g) ----------> 2 Fe(s) + 3 CO₂ (g)

Fe : Fe₂O₃ = 2 : 1

Fe : CO = 2 : 3

Fe : CO₂ = 2 : 3

4.

2 NaOH (aq.) + CO₂ (g) -----------> Na₂CO₃ (aq.) + H₂O (l)

(a)

From the balanced equation,

1 mol CO₂ = 2 mol NaOH

Then,

0.5 mol CO₂ = 1 mol NaOH

(b)

1 mol CO₂ = 1 mol Na₂CO₃

Then,

0.5 mol CO₂ = 0.5 mol Na₂CO₃