(4Ga + 3S2 → 2Ga2S3) 1. How many moles of Sulfur are needed to react with 12.5 moles of Gallium

9.375

Explanation:

According to the chemical equation, for every 4 moles of gallium, 3 moles of sodium are needed to react.  Set up a ratio using this relationship to solve.

4/3 = 12.5/x

4x = 37.5

x = 9.375

You need 9.375 moles of sulfur.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.