Question #e15e7

1 Answer
Ernest Z.
May 1, 2017

You must use "69.68 g of Na"_2"S"69.68 g of Na2S to produce "50.00 g of TiS"_250.00 g of TiS2.

Explanation:

There are four steps to answering this type of stoichiometry problem.

  1. Write the balanced equation for the reaction.
  2. Use the molar mass of "TiS"_2TiS2 to convert grams of "TiS"_2TiS2 to moles of "TiS"_2TiS2.
  3. Use the molar ratio from the balanced equation to convert moles of "TiS"_2TiS2 to moles of "Na"_2"S"Na2S.
  4. Use the molar mass of "Na"_2"S"Na2S to convert grams of "Na"_2"S"Na2S to moles of "Na"_2"S"Na2S.

Step 1. Write the balanced equation.

"2Na"_2"S" + "TiCl"_4 → "4NaCl" + "TiS"_22Na2S+TiCl4→4NaCl+TiS2

Step 2. Convert grams of "TiS"_2TiS2 to moles of "TiS"_2TiS2.

The molar mass of "TiS"_2TiS2 is 112.00 g/mol.

50.00 cancel("g TiSO"_2) × ("1 mol TiSO"_2)/(112.00 cancel("g TiS"_2)) = "0.446 43 mol TiS"_2

Step 3. Use the molar ratio to calculate the moles of "Na"_2"S".

From the balanced equation, the molar ratio is "2 mol Na"_2"S":"1 mol TiS"_2.

"0.446 43" cancel("mol TiS"_2) × ("2 mol Na"_2"S")/(1 cancel("mol TiS"_2)) = "0.892 86 mol Na"_2"S"

Step 4. Convert moles of "Na"_2"S" to grams of "Na"_2"S".

"0.892 86" color(red)(cancel(color(black)("mol Na"_2"S"))) × ("78.04 g Na"_2"S")/(1 color(red)(cancel(color(black)("mol Na"_2"S")))) = "69.68 g Na"_2"S"

You need to use "69.68 g of Na"_2"S".

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