Question

1.How many moles of each element are in 0.0250 mol of K 2 Cr O 4?

Answer 1

Answer:

1. In 0.0250 moles of potassium chromate there are 0.05 moles of potassium , 0.025 moles of chromium and 0.1 moles of oxygen are present.

2. In 4.50 moles of ammonium carbonate there are 9 moles of ammonium ions and 4.5 moles of carbonate ions are present.

Explanation:

1.

Moles of potassium chromate = 0.0250 mol

Formula of potassium chromate = $K_2CrO_4$

1 mole of potassium chromate has 2 moles of potassium , 1 mole of chromium and 4 moles of oxygen.

Then in 0.0250 moles of potassium chromate:

Moles of potassium will be:

$2\times 0.0250 mol= 0.05 mol$

Moles of chromium will be:

$1\times 0.0250 mol= 0.025 mol$

Moles of oxygen will be:

$4\times 0.0250 mol= 0.1 mol$

2.

Moles of ammonium carbonate = 4.50 mol

Formula of ammonium carbonate =$(NH_4)_2CO_3$

1 mole of ammonium carbonate has 2 moles of ammonium ion and 1  mole of carbonate ion.

Then in 4.50 moles of ammonium carbonate:

Moles of ammonium ion will be:

$2\times 4.50 mol= 9mol$

Moles of carbonate ions will be:

$1\times 4.50 mol= 4.5 mol$