Question

Ca + 2H2O --> Ca(OH)2 + H2

40g of Ca is mixed with 100g of water. Calculate mass of solution left after reaction is complete.​

Answer 1

`\boxed{\text{138 g}}`

Step-by-step explanation:

Ca(s) + 2H₂O(ℓ) ⟶ Ca(OH)₂(s) + H₂(g)

Mass of reactants = mass of products

You have 140 g of reactants, so you should get 140 g of products.

The calcium hydroxide and the left-over water will remain in the beaker, but the hydrogen will escape.

According to the equation, 1 mol (40 g) of Ca produces 1 mol (2.0 g) of hydrogen.

Mass of suspension + mass of hydrogen = 140 g

Less mass of hydrogen = 2.0 g

Mass of suspension = 138 g

`\text{The mass of the suspension is $\boxed{\textbf{138 g}}$}`