Show your solution and provide units.
1. Calculate the volume (in mL) of 2.25 M HNO3 solution required to react with 24.2 mL of 3.50 M NaOH solution.
2.What volume (in mL) of 4.35 M HCl solution is needed to react with 18.5 g of CA(OH)2 ?
3.How many grams of silver chromate (Ag2CrO4) will precipitate when 86.0 mL of 0.200 M silver nitrate (AgNO3) is added to 50.0 mL of 0.300 M chromate (K2CrO4)? ( Molar mass of Ag2CrO4 = 331.74 g/ mol).
1. HNO3 + NaOH → NaNO3 + H2O
Proportion:
3.50 mol – 1000 mL
x mol – 24.2 mL
x = n(NaOH) "= \\frac{3.50 \\times 24.2}{1000} = 0.0847 \\;mol"
According to the reaction equation:
n(HNO3) = n(NaOH) = 0.0847 mol
Proportion:
4.35 mol – 1000 mL
0.0847 – y mL
V(HNO3) "= \\frac{0.0847 \\times 1000}{4.35} = 19.47\\;mL"
2. 2HCl + Ca(OH)2 → CaCl2 + 2H2O
M(Ca(OH)2) = 74.09 g/mol
n(Ca(OH)2) "= \\frac{18.5}{74.09} = 0.249 \\;mol"
According to the reaction equation:
n(HCl) = 2n(Ca(OH)2) "= 2 \\times 0.249 = 0.498 \\;mol"
Proportion:
4.35 mol – 1000 mL
0.498 mol – x mL
x = V(HCl) "= \\frac{0.498 \\times 1000}{4.35} = 114.5 \\;mL"
3. 2AgNO3 + K2CrO4 → Ag2CrO4 + 2KNO3
n(AgNO3) "= \\frac{0.200 \\times 86.0}{1000} = 0.0172 \\;mol"
n(K2CrO4) "= \\frac{0.300 \\times 50.0}{1000} = 0.015 \\;mol"
Accordinf to the reaction for one mole of K2CrO4 we need two moles of AgNO3.
So, AgNO3 is the limiting reactant.
n(Ag2CrO4) = "\\frac{1}{2}" n(AgNO3) "= \\frac{1}{2} \\times 0.0172 = 0.0086 \\;mol"
m(Ag2CrO4) "= 0.0086 \\times 331.74 = 2.85 \\;mol"
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