Question

Be sure to answer all parts.

Answer 1

Answer:

38.7%

41.3%

20%

Explanation:

The percentage composition helps to know the what percent of the total mass of a compound is made up of each of the constituent elements or groups.

To solve this problem:

• find the formula mass by adding the atomic masses of the atoms that makes up the compound.
• place the mass contribution of the element or group to the formula mas and multiply by 100;

Compound:

 Ca₃(PO₄)₂

  Formula mass = 3(40) + 2[31 + 4(16)]

                           = 120 + 2(95)

                           = 120 + 190

                           = 310

%C = $\frac{3(40)}{310}$ x 100  = 38.7%

%P = $\frac{8(16)}{310}$ x 100  = 41.3%

%O = $\frac{2(31)}{310}$ x 200  = 20%