Question

Answer the following questions pertaining to the following equation. 4Ga + 3S2 -> 2Ga2S3

1. How many moles of Sulfur are needed to react with 12.5 moles of Gallium

2. How many moles of Sulfur are needed to react with 100.0 grams of Gallium?

3. How many grams of Gallium burned if 200.0 grams of aluminum oxide formed?

4. How many grams of Gallium Sulfide would form if 20.5 moles of Gallium burned?

Answer 1

Solution1:Here the reaction given is 4Ga+3S22Ga2S3.

12.5 moles Ga=12.5*69.72=871.5g Gallium.

12.5 moles of Ga=871.5 g of Ga

4 moles of Ga=4*871.5/12.5=278.88 g Ga is required with 3 mole of S to form 2 moles of 2Ga2S3 in reaction.

4 molecules of Ga=12.5 moles of Ga

1 molecule of Ga=12.5/4=3.125 moles of Ga

Similarly, 3moles of S2=192.39 grams

4 moles of Ga=12.5 moles in reaction  

3mole of Ga=3*12.5/4=9.375 moles of S2 are needed to react with 12.5 moles of Ga.

Solution 2: 69.723 grams= 1mole of Ga

100 grams=1.4342 moles of Ga

4 moles of Ga= 278.89 grams of Ga

In reaction 4 moles of Ga=3 moles of S2.

278.89 grams Ga=192.39 grams of S2

100 grams of Ga=192.39*100/278.89=68.98 grams S2 are needed.

Solution 3:200 grams of Ga2S3= 0.8487 mole of Ga2S3

To make 2 moles Ga2S3, 4 moles of Ga is required

for 0.8487 moles Ga2S3=1.6974 moles of Ga is needed.

1 mole of Ga=69.723 g Ga

1.6974 mole of Ga=118.34 grams Ga is burned.

Soltion 4: 4 moles of Ga is required to form 2 moles of 2Ga2S3........(1)

If 20.5 gram Ga burned= 4 moles of Ga

1 mole of Ga=20.5/4=5.12 mole of Ga

From statement (1) number of moles of Ga required to burn to form Ga2S3=5.12*2=10.24 moles.

1 mole of Ga2S3=235.64 grams Ga2S3

10.24 moles of Ga2S3=2412.96 grams Ga2S3.