What mass of calcium chloride is needed to react with 2.50 grams of sodium carbonate

2.62g

Explanation:

Given parameters:

Mass of Na₂CO₃  = 2.5g

Unknown:

Mass of CaCl₂  = ?

Solution:

We have to work from the known to the unknown using their molar relationships.

The known is the given mass of Na₂CO₃.

  We must make sure the reaction equation is balanced before we start working with it;

    Na₂CO₃   +   CaCl₂   →    2NaCl   + CaCO₃

Now,

Number of moles of Na₂CO₃  =

 Molar mass of Na₂CO₃ = 2(23) + 12 + 3(16)  = 106g/mol

 Number of moles  =  = 0.024mole

  1 mole of  Na₂CO₃ reacted with 1 mole of CaCl₂

 0.024mole of Na₂CO₃ will react with 0.024mole of CaCl₂

Mass of CaCl₂ = number of moles x molar mass

Molar mass of CaCl₂ = 40 + 2(35.5) = 111g/mole

 Mass of CaCl₂ = 0.024  x 111 = 2.62g