# Question #17866

Jun 14, 2017

The mixture is 35.7 % $\text{Mg"^"+}$ and 64.3 % $\text{Mg"^"2+}$.

#### Explanation:

Let $x$ be the fraction of $\text{Mg}$ that absorbs 750 kJ.

Then (1-x) is the fraction that absorbs 1450 kJ.

$750 x + 1450 \left(1 - x\right) = 1200$

$750 x + 1450 - 1450 x = 1200$

$700 x = 250$

$x = \frac{250}{700} = 0.357$

∴ The mixture is 35.7 % $\text{Mg"^"+}$ and 64.3 % $\text{Mg"^"2+}$.