Question

an analytical chemist measures the amount of elements $e_1$ and $e_2$ in four samples of an unknown substance $x$:

sample	mass of $e_1$	mass of $e_2$
2	5.3 g	27.7 g
3	4.5 g	23.5 g
4	3.8 g	20.2 g

its known that $x$ contains no elements other than $e_1$ and $e_2$.
using this information, answer the questions in the table below.
is $x$ a pure substance or a mixture? if you dont have enough information to decide, choose cant decide.
if you said $x$ is a pure substance, calculate the mass of element $e_1$ the analytical chemist would find in a new 10.0 g sample of $x$. round your answer to 2 significant digits.

Explanation:

Step1: Calculate mass - ratios for each sample

For sample 1: $\frac{\text{mass of }E_1}{\text{total mass}}=\frac{4.6}{4.6 + 14.4}=\frac{4.6}{19}\approx0.242$
For sample 2: $\frac{\text{mass of }E_1}{\text{total mass}}=\frac{5.3}{5.3+27.7}=\frac{5.3}{33}\approx0.161$
For sample 3: $\frac{\text{mass of }E_1}{\text{total mass}}=\frac{4.5}{4.5 + 23.5}=\frac{4.5}{28}\approx0.161$
For sample 4: $\frac{\text{mass of }E_1}{\text{total mass}}=\frac{3.8}{3.8+20.2}=\frac{3.8}{24}\approx0.158$
Since the mass - ratios of $E_1$ to the total mass are not constant across the samples, $X$ is a mixture.

Answer:

mixture