Question

What mass of calcium carbonate (in grams) can be dissolved by 4.0 g of hcl? (hint: begin by writing a balanced equation for the reaction between hydrochloric acid and calcium carbonate.)?

Answer 1

The reaction between calcium carbonate and hydrochloric acid can be expressed through the chemical reaction,

    CaCO3 + 2HCl --> CaCl2 + H2O + CO2

The molecular weight of calcium carbonate is 100 g/mol while that of hydrochloric acid is 36.45. The equation above depicts that 100 g of calcium carbonate can be dissolved in 72.9 g of hydrochloric acid. 

    x = (4 g HCl)(100 g CaCO3 / 72.9 HCl)
      x = 5.49 g

Answer: 5.49 g

Answer 2

Answer:

4 grams of HCl need 5.486 grams of CaCO3

Explanation:

The balanced chemical reaction between hydrocloric acid and calcium carbonate can be expressed as

CaCO3+ 2HCl -> CaCl2 + CO2 + H2O

This means that 1 mole of CaCO3 reacts with 2 mole of HCl to produce 1 mole of CaCl2,CO2 and H2O.

2 mole of HCl needs 2 mole of CaCO3  

In term of mass we can write that

72.9 grams of HCl need 100 grams of CaCO3

1 grams of HCl need (100/72.9) grams of CaCO3

4 grams of HCl need ((100*4)/72.9) grams of CaCO3

4 grams of HCl need 5.486 grams of CaCO3