Question

Given the equation Ca + H2O --> Ca(OH)2 + H2 how many grams of calcium will react completely with 10.0 grams of water? *

Answer 1

Answer: 11.0 g of calcium will react with 10.0 grams of water.

Step-by-step explanation:

To calculate the moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}`

moles of
`H_2O`

`\text{Number of moles}=(10.0g)/(18g/mol)=0.55moles`

The balanced chemical equation is:

`Ca+2H_2O\rightarrow Ca(OH)_2+H_2`

According to stoichiometry :

2 moles of
`H_2O` require = 1 mole of
`Ca`

Thus 0.55 moles of
`H_2O` require=
`(1)/(2)* 0.55=0.275moles` of
`Ca`

Mass of
`Ca=moles* {\text {Molar mass}}=0.275moles* 40g/mol=11g`

Thus 11.0 g of calcium will react with 10.0 grams of water.