Concept explainers
4.47 Silicon carbide is, an abrasive used in the manufacture of grinding wheels. A company is investigating whether they can be more efficient in the construction of such wheels by making their own SiC via the reaction
(a) If this reaction consistently has a yield of 85%, what is the minimum amount of both silicon dioxide and carbon needed to produce 3400 kg of SiC for the manufacture of cutting wheels? (b) The silicon dioxide is to he obtained from sand and the carbon is derived from coal. If the available sand is 95% SiO2 by weight and the coal is 73% C by weight, what mass of coal is needed for each metric ton of sand used?
a.
To determine: The minimum amount of both silicon dioxide and carbon needed to produce
Explanation of Solution
Step 1: Balance Reaction
Reaction is already balanced
Step 2: Change all amounts to mol
Step 3: Relate stoichiometry
Now, for carbon:
Step 4: Calculate mass
For SiO2
Now, for carbon
Step 5: Correct for actual yield
b.
To determine:
Mass of coal needed for each metric ton of sand used.
Explanation of Solution
Now, relate new amounts.
Step 1: Relate 1 metric ton of sand:
Step 2: Use Ratio between reactants:
Step 3:Calculate mass of coal
a.
b.
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Chapter 4 Solutions
Chemistry for Engineering Students
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