Question #e15e7

1 Answer
May 1, 2017

Answer:

You must use #"69.68 g of Na"_2"S"# to produce #"50.00 g of TiS"_2#.

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"_2# to convert grams of #"TiS"_2# to moles of #"TiS"_2#.
  3. Use the molar ratio from the balanced equation to convert moles of #"TiS"_2# to moles of #"Na"_2"S"#.
  4. Use the molar mass of #"Na"_2"S"# to convert grams of #"Na"_2"S"# to moles of #"Na"_2"S"#.

Step 1. Write the balanced equation.

#"2Na"_2"S" + "TiCl"_4 → "4NaCl" + "TiS"_2#

Step 2. Convert grams of #"TiS"_2# to moles of #"TiS"_2#.

The molar mass of #"TiS"_2# 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"#.