Answer:
The products of 1.0 kg of calcium phosphate reacting with 1.0 kg concentrated sulfuric acid (98% H2SO4 by mass) are:
- <em>1.3 kg of Calcium sulfate.</em>
- <em>0.6 kg of Phosphoric acid</em>
- <em>And 0.03 kg of unconsumed sulfuric acid and 0.02 kg of impurities in the sulfuric acid.</em>
Explanation:
Step 1.
The <em>balanced equation </em>of the reaction is required. For this case is:
Where:
- is Sulfuric Acid.
- is Calcium Phosphate.
- is Calcium Sulfate.
- is Phosphoric acid.
Step 2.
The <em>molar masses</em> (the weight of one mol) of each compound are required:
- Sulfuric Acid: 98.079 g/mol
- Calcium Phosphate: 310.18 g/mol
- Calcium Sulfate: 136.14 g/mol
- Phosphoric acid: 97.994 g/mol
Step 3.
The amount of moles of sulfuric acid and calcium phosphate avalaible are calculated using the corresponding <em>molar mass</em>.
- For sulfuric acid: (note that the real amount of acid is the purity times the weight)
- For calcium phosphate: .
Step 4.
From the balanced equation in Step 1. It is known that:
<em>3 moles of Sulfuric acid need 1 mol (no coefficient) of Calcium phosphate to react</em>.
Then is possible to determinate which of the reagents is first totally consumed (<em>limiting reagent</em>).
- For sulfuric acid: For 3 moles of sulfuric acid only one mol of calcium phosphate is required. Then the 9.99 moles would need 3.33 moles of calcium phosphate (more than available).
- For calcium phosphate: 1 mol of calcium phosphate will require 3 moles of sulfuric acid. Then, the 3.22 moles would need 9.67 moles of sulfuric acid (less than the 9.99 available).
Then, is possible to conclude that all the calcium phosphate would be consumed (It is the limiting reagent), and some sulfuric acid would remain.
Step 4.
Using the determined limiting reagent and, from the balanced equation of step 1, it is possible to know that:
<em>For each 1 mol of calcium phosphate consumed: 3 moles of calcium sulfate and, 2 moles of phosphoric acid would be produced.</em>
With this information:
- Calcium sulfate: produced.
- Phosphoric acid: produced.
- Sulfuric acid: As there is more sulfuric acid (9.99 mol) that the 9.67 required, then 0.32 mol remains after the calcium phosphate is depleted.
Step 5.
Using the molar masses in the step 2, is possible to calculate the weight of each species in the products.
- Calcium sulfate: produced.
- Phosphoric acid: produced.
- Sulfuric acid: unused and 0.02 kg of impurities in the original sulfuric acid (98% acid, and 2% impurities).