Copper metal (Cu) reacts with silver nitrate (AgNO3) in aqueous solution to form Ag and Cu(NO3)2. An excess of AgNO3 is present. The balanced chemical equation is shown below. Cu + 2AgNO3 Right arrow. Cu(NO3)2 + 2Ag

The molar mass of Cu is 63.5 g/mol. The molar mass of Ag is 107.9 g/mol. What mass, in grams, of Ag is produced from reaction of 31.75 g of Cu?
26.95
107.9
215.91
431.82

107.9g

Explanation:

Given parameters:

Molar mass of Cu  = 63.5g/mol

Molar mass of Ag  = 107.9g/mol

Mass of reacting Cu  = 31.75g

Unknown:

Mass of Ag produced  = ?

Solution:

The reaction equation is given as;

    Cu + 2AgNO₃ →  Cu(NO₃)₂ + 2Ag

The equation is balanced.

We start by find the number of moles of the known;

  Number of moles  =  

  Number of moles of Cu  =   = 0.5moles

From the balanced equation;

       1 mole of Cu produced 2 moles of Ag;

      0.5 mole of cu will produce 0.5 x 2 mole of Ag  = 1 mole of Ag

Now;

 Mass of Ag  = number of moles x molar mass

 Mass of Ag  = 1 mole of Ag x 107.9g/mol  = 107.9g