Question

Calculate the number of moles of
(a)chloride ions in 79.17 g of magnesium chloride, MgCl2

Answer 1

Explanation:

Explanation:

Step 1: Write out the chemical formula of the compound.

Magnesium Chloride = MgCl2

Step 2: Convert moles into number of compounds using Avogadro's number

0.5 molesMgCl2⋅(6.022⋅10231 moleMgCl2)=3.011⋅1023

Step 3: Determine how many Chloride ions there will be in 1 compound

There will be 2 Cl− ions in each compound (Cl2 part)

Step 4: Multiply the number from Step 2 by the number in Step 3

3.011⋅1023⋅2=6.022⋅1023

We do this because the ratio is 2 Cl− ions for every 1 compound.

In the case of finding how many ions in general (both sodium and chloride), we would multiply by 3 because there are 3 ions per 1 compound.

Step 5: All done!