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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: goingthroughthemotions on July 29, 2019, 09:06:56 PM

Title: Can you check my hw answers - spent hours on this
Post by: goingthroughthemotions on July 29, 2019, 09:06:56 PM

Hi there.
I am in a community college chemistry class and have an assignment I would like checked before I turn it in. I would greatly appreciate the confirmation/possible needed corrections. I have spent hours on this going back and forth on a couple of questions. Thank you.

1) When 56.6g of calcium is reacted with nitrogen gas, 32.4g of calcium nitride is produced. What is the % yield for this reaction?
Choices: 15.6%, 46.5%, 78.4% or 94.3%. I selected 15.6%.

This is the balanced formulat for the following questions. 2NH3 + 3CuO -> 3Cu + 3H2O.

2) What element is reduced in this equation?
Choices: Cu, N, O, or H. I selected Cu.

3) 18 g of NH3 is mixed with 90 g of CuO. How many moles of NH3 are present?
Choices: 2, 1, 0.5, 1.5. I selected 1.


4) 18 g of NH3 is mixed with 90 g of CuO. How many moles of CuO are present?
Choices: 1, 0.5, 2, 3. I selected 1 again.

5) 18 g of NH3 is mixed with 90 g of CuO. What is the limiting reactant?
Choices: CuO or NH3. I selected CuO.

Title: Re: Can you check my hw answers - spent hours on this
Post by: Borek on July 30, 2019, 02:46:31 AM

Quote from: goingthroughthemotions on July 29, 2019, 09:06:56 PM

I selected 15.6%.

This is something that you should calculate, can you show how you got 15.6%?

Quote

This is the balanced formulat for the following questions. 2NH3 + 3CuO -> 3Cu + 3H2O

It is not balanced, there is no nitrogen on the right.

Your answers to questions 2, 3, 4 and 5 are more or less correct, sadly in 3 and 4 technically there are no correct answers between those to choose from.