# Question ea84f

May 24, 2017

$0.40$ mol

#### Explanation:

You are given CuSO""_4*5H""_2O

Strategy: First find the weight of hydrated copper sulfate in grams per mole. Then, using that discovery as a conversion factor, find the number of moles in 100 grams.

Weight of hydrated copper sulfate

Step 1. Get the atomic mass and number of each atom per molecule

• Cu: 1 copper atom at 63.456 g/mol

• S: 1 sulfur atom at 32.06 g/mol

• O""_4: 4 oxygen atoms at 15.999 g/mol

• 5(H""_2): 10 hydrogen atoms at 1.008 g/mol

• 5(O): 5 oxygen atoms at 15.999 g/mol

Step 2. Multiply and add the terms of get the number of moles found in one gram.

$1 \times 63.456 + 1 \times 32.06 + 9 \times 15.999 + 10 \times 1.008 = 249.6$ g/mol

The number of moles
Step 3. Multiply 100 grams times that result as a conversion factor.

100" g"xx ((1" mol")/(249.6" g")) =0.40 mol

Because 1 mole is equivalent to $6.02 \times {10}^{23}$ objects, there are $2.41 \times {10}^{23}$ molecules in CuSO""_4*5H""_2#O.