# Question 0e4b8

Jun 10, 2015

21.1% of the marble was pure ${\text{CaCO}}_{3}$.

#### Explanation:

Step 1. Write the chemical equation for the reaction.

${\text{CaCO"_3 + "Ba(NO"_3)_2 → "Ca(NO"_3)_2 + "BaCO}}_{3}$

Step 2. Calculate the theoretical yield of ${\text{BaCO}}_{3}$.

${\text{Theoretical yield" = 3.00 cancel("g CaCO₃") × (1 cancel("mol CaCO₃"))/(100.09 cancel("g CaCO₃")) × (1 cancel("mol BaCO₃"))/(1 cancel("mol CaCO₃")) × ("197.34 g BaCO"_3)/(1 cancel("mol BaCO₃")) = "5.915 g BaCO}}_{3}$

Step 3. Calculate the percent yield.

"% yield" = "actual yield"/"theoretical yield" × 100 % = (1.25 cancel("g"))/(5.915 cancel("g")) × 100 % = 21.1 %#

You got only 21.1 % of the expected yield of ${\text{BaCO}}_{3}$, so the marble was only 21.1 % pure ${\text{CaCO}}_{3}$.