Hello I’m need to wyzant and my school is almost over. I need help completing my homework as soon as possible before the deadline please please help me.

Question

1. 3 Cu + 8HNO3 g 3 Cu(NO3)2   + 2 NO + 4 H2O

In the above equation how many moles of NO can be made when 58 moles of HNO3 are consumed?

 

1. 2 NH3 + 3 CuO g 3 Cu + N2 + 3 H2O

In the above equation how many moles of water can be made when 44 moles of NH3 are consumed?

please help me by solving and explaining

Answer 1

You can solve these problems with one of my favorite tools, dimensional analysis. This is a method of completing complex unit conversions using one or more known ratios. If you set things up correctly, then the units you don't want get cancelled out and you're left with the units you do want. Let's start with question 1.

1. 3 Cu + 8HNO3 g 3 Cu(NO3)2   + 2 NO + 4 H2O

In the above equation how many moles of NO can be made when 58 moles of HNO3 are consumed?

So we start with 58 moles HNO3, and it's asking for moles N0.

58 moles HNO3

From this equation, we know for every 8 moles of HNO3 consumed 2 mol NO are made. So we can put that relationship into our problem.

58mol HNO3 * 2mol NO/(8 mol HNO3)

When you multiply this, mol HNO3 will be on both top and bottom and cancel out, so we just get mol NO, which is: 14.5mol NO

We can use the same process for the next problem.

1. 2 NH3 + 3 CuO g 3 Cu + N2 + 3 H2O

In the above equation how many moles of water can be made when 44 moles of NH3 are consumed?

I'll fill out the fractional analysis, use the solution above and pen and paper to follow my reasoning.

44 mol NH3 * (3 mol H2O/2 mol NH3) = 66mol H2O

For practice, try solving this problem. For the same equation and same amount of NH3, how many moles of nitrogen gas can be made?

For even more challenge! How many grams of water will be produced if 10g NH3 are consumed?