Question

10. In dilute nitric acid, copper metal dissolves according to the following balanced equation:

Cu + 4 HNO3 → Cu(NO3)2 + 2 NO2 + 2 H2O

a) How many grams of nitric acid are required to dissolve 11.45 g of Cu?

b) How many grams of NO2 gas are formed?

Answer 1

a)

mass of Cu = 11.45 g

molar mass of Cu = 63.55 g/mol

mol of Cu = (mass)/(molar mass)

= 11.45/63.55

= 0.1802 mol

According to balanced equation

mol of HNO3 formed = (4/1)* moles of Cu

= (4/1)*0.1802

= 0.7207 mol

mass of HNO3 = number of mol * molar mass

= 0.7207*63.018

= 45.4 g

Answer: 45.4 g

b)

According to balanced equation

mol of NO2 formed = (2/1)* moles of Cu

= (2/1)*0.1802

= 0.3603 mol

mass of NO2 = number of mol * molar mass

= 0.3603*46.01

= 16.6 g

Answer: 16.6 g