Answer:
The answer to your question is below
Explanation:
21.-
mass of Cr = ?
mass of Cu = 27 g
balanced chemical reaction
2Cu + 3CuSO₄ ⇒ Cr₂(SO₄)₃ + 3 Cu
-Look for the molar mass of Copper and chromium
Cr = 52 g
Cu = 63.6 g
52 g of Cr -------------- 63.5 g of Cu
x -------------- 27 g of Cu
x = (27 x 52) / 63.5 g
x = 22.1 g of Cr
22.-
Theoretical yield of NO₂ = ?
mass of Pb(NO₃)₂
Balanced chemical reaction
2Pb(NO₃)₂ ⇒ 2PbO + 4NO₂ + O₂
Process
-Calculate the molar mass of Pb(NO₃)₂ and NO₂
Pb(NO₃)₂ = 2 [ 207 + (14 x 2) + (16 x 6)]
= 2[207 + 28 + 96]
= 662 g
NO₂ = 4[ 14 + (16 x 2)]
= 4[14 + 32]
= 184 g
- Calculate the theoretical yield
662 g pf Pb(NO₃)₂ ----------------- 184 g of NO₂
9.95 g of Pb(NO₃)₂ -------------- x
x = (9.95 x 184) / 662
x = 2.76 g of NO₂
-Percent yield
Percent yield = actual yield / theoretical yield x 100
= 2.12/2.76 x 100
= 76.8 %
23.-
balanced chemical reaction
2SO₂ + O₂ + 2H₂O ⇒ 2H₂SO₄
mass of O₂ = ?
mass of H₂SO₄ = 56.1 g
-calculate the molar mass of O₂ and H₂SO₄
O₂ = 32 g
H₂SO₄ = 2[2 + 32 + 64] = 196 g
32 g of O₂ --------------- 196 g of H₂SO₄
x ---------------- 56.1 g of H₂SO₄
x = (56.1 x 32) / 196
x = 1795.2 / 196
x = 9.2 g of O₂
