Chemistry Help?

[E M ! L E Y]

40.0g o pentane react in a combustion reaction the actual yeild of carbon dioxide was 115g
1) write a balanced equation
2)using a mass-mass equation and the balanced equation above determine the theoretical yeild of carbon dioxide
3)using the actual yeild and theoreticla yeild from above determine the percent yeild of carbon dioxide

113.2g of aluminum sulfate react with excess barium chloride in a double displacemnet reaction to produce 68.2g of aluminum chloride (actual yeild) abd one other product
1) write a balanced equation
2)using a mass-mass equation and the balanced equation above determine the theoretical yeild of aluminum chloride
3)using the actual yeild and theoreticla yeild from above determine the percent yeild of aluminum chloride

the amount of product in a givenreaction turns out to be only 2.65g although the theoretical amount was calculated to be 2.75g. what is the percent yeild?

thank y'all in advance