Homework Helpers discussion

Post any chemistry questions you have here, but remember that no one is to give answers! No one! All you can do is get help here. Not straight-out answers, or you won't know how to do your work in the future.

I took a college chemistry class so hopefully I'll be able to help some.

i have chemistry homework can anyone help me?

I can try to help :p

thanks

so these are the ones i'm stuck on:

1. calculate the percentage nitrogen in ammonia (NH3)
2. Calculate the percentage yield when 1.8g of calcium carbonate was obtained when the theoretical amount was 2.0g .
3. Calculate the mass of 12,000cm3 of Carbon Dioxide.
4. what mass of calcium oxide could be made from 75tonnes of limestone (CaCO4)
CaCO3 - CaO + CO2

Also 1000cm3 = 1dm3 i think
Also is number one atom economy?

I can help you with problem 1.

Atomic mass of nitrogen= 14
Molecular mass of ammonia (NH3)= 17

So, to get the answer all you have to do is solve:

14/17 x 100

Ok for the second one,

The expected amount was 2.0g. The amount you actually got was 1.8g. percentage yield is basically actual yield/theoretical yield. so Actual Yield/Theoretical Yield X 100 gives you percentage yield.

okay thanks both of you!