Question

Please help :((

Ca + 2H2O --> Ca(OH)2 + H2 If 25.0 g water reacts with excess calcium solid,
a) Find grams of hydrogen gas produced
b) Find moles of Ca(OH)2 made.

Answer 1

0.7 moles of Ca(OH)₂ are produced.

Mass of hydrogen gas = 1.4 g

Step-by-step explanation:

Given data:

Mass of water = 25.0 g

Mass of hydrogen gas produced = ?

Number of moles of Ca(OH)₂ formed = ?

Solution:

Chemical equation:

Ca + 2H₂O → Ca(OH)₂ + H₂

Number of moles of water:

Number of moles = mass/molar mass

Number of moles = 25.0 g/ 18 g/mol

Number of moles = 1.4 mol

Now we will compare the moles of water with hydrogen:

H₂O : H₂

2 : 1

1.4 : 1/2×1.4 = 0.7 mol

Mass of hydrogen gas produced:

Mass = number of moles × molar mass

Mass = 0.7 mol × 2 g/mol

Mass = 1.4 g

Now we will compare the moles of water and Ca(OH)₂

H₂O : Ca(OH)₂

2 : 1

1.4 : 1/2×1.4 = 0.7 mol

Thus, 0.7 moles of Ca(OH)₂ are produced.