Step-by-step explanation:
Cu(NO₃)₂ + 2 KOH ----> Cu(OH)₂ + 2 KNO₃
We have to find the mass of Cu(OH)₂ that is produced in the reaction of 7.6 g of Cu(NO₃)₂ with 6.2 g of KOH.
We have to find the limiting reagent. To do that, we will find the mass that is produceb by each reactant considering that is reacting with an excess of the other one.
Let's find the mass of Cu(OH)₂ produced by 7.6 g of Cu(NO₃)₂.
mass of Cu(NO₃)₂ = 7.6 g
molar mass of Cu(OH)₂ = 97.56 g/mol
molar mass of Cu(NO₃)₂ = 187.56 g/mol
1 mol of Cu(NO₃)₂ = 1 mol of Cu(OH)₂ ---> molar ratio
7.6 g of Cu(NO₃)₂ * (1 mol of Cu(NO₃)₂/187.56 g of Cu(NO₃)₂) * (1 mol of Cu(OH)₂/1 mol of Cu(NO₃)₂) * (97.56 g of Cu(OH)₂/1 mol of Cu(OH)₂) = 3.95 g of Cu(OH)₂
We found that 7.6 g of Cu(NO₃)₂ will produce 3.95 g of Cu(OH)₂. Let's find the mass of Cu(OH)₂ that will be produced by 6.2 g of KOH.
mass of KOH = 6.2 g
molar mass of Cu(OH)₂ = 97.56 g/mol
molar mass of KOH = 56.11 g/mol
2 mol of KOH = 1 mol of Cu(OH)₂ ---> molar ratio
6.2 g of KOH * (1 mol of KOH/56.11 g of KOH) * (1 mol of Cu(OH)₂/2 moles of KOH) * (97.56 g of Cu(OH)₂/1 mol of Cu(OH)₂) = 5.39 g of Cu(OH)₂
6.2 g of KOH will produce 5.39 g of Cu(OH)₂. So the limiting reactant is Cu(NO₃)₂ and KOH is in excess.
Answer: 3.95 g of Cu(OH)₂ is produced.