Question

current attempt in progress
a 7.455 g sample of kcl contains 3.545 g of cl. what is the percent by mass of potassium in kcl?
52.45%
47.55%
39.10%
35.35%

Explanation:

Step1: Find mass of potassium

The mass of the KCl sample is 7.455 g and the mass of Cl is 3.545 g. Using the formula $m_{K}=m_{KCl}-m_{Cl}$, we have $m_{K}=7.455 - 3.545=3.91$ g.

Step2: Calculate percent - by - mass of potassium

The percent - by - mass formula is $\text{Percent by mass of }K=\frac{m_{K}}{m_{KCl}}\times100\%$. Substitute $m_{K}=3.91$ g and $m_{KCl}=7.455$ g into the formula: $\frac{3.91}{7.455}\times 100\%\approx52.45\%$.

Answer:

52.45%