Question

Calculate the mass % of K in potassium phosphate
Calculate the mass % of O in potassium phosphate

Answer 1

Answer:

$\large \boxed{\mathbf{1. \, \,55.26 \, \%; \, \,2. \, \,30.15 \, \% }}$

Explanation:

1. Mass percent of K

$\begin{array}{cccr}\mathbf{Atoms} & \textbf{Contribution} & & \textbf{Subtotal}\\\text{3K} & 3 \times 39.10 & = & 117.30\\\text{1P} & 1 \times 30.97 & = & 30.97\\\text{4O} & 4 \times 16.00 & = &64.00\\& \text{TOTAL} & = & \mathbf{212.27}\\\end{array}$

$\text{Percent K} = \dfrac{\text{117.30 g}}{\text{212.27 g}} \times \, 100\% = \mathbf{55.26 \, \%}\\\text{The percent by mass of potassium is \large \boxed{\mathbf{55.26 \, \% }} }$

2. Mass percent of O

$\text{Percent O} = \dfrac{\text{64.00 g}}{\text{212.27 g}} \times \, 100\% = \mathbf{30.15 \, \%}\\\text{The percent by mass of oxygen is \large \boxed{\mathbf{30.15 \, \% }} }$