posted by Andy on .
3Cu+8HNO3--> 3Cu(NO3)2+ 2NO+4H2O
How many moles of HNO3 are required to react with 6 moles of Cu?
How many moles of Cu(NO3)2 are produced when 3 moles of Cu react?
How many moles of Cu must react to produce 4 moles of NO?
If 4 moles of NO are produced, how many moles of H2O are also produced?
How to go about solving these questions? Please help.
It's all done with the balanced equation and the coefficients. Here is an example. Note how the FACTOR converts from one material to the other.
mols NO = 4. We want to convert to mols Cu.
mols Cu = mols NO x (factor)
factor is 3 mols Cu/2mols NO. So
mols Cu = 4 mols NO x (3 mols Cu/2 mols NO) = 4 x 3/2 = 12/2 = 6
You COULD have written the factor as the reciprocal; i.e., 2 mols NO/3 mols Cu BUT note that the units would not cancel if you did that. So the factor ALWAYS is used so that the unit we don't want cancels and the unit we want the answer to be in is left. Post your answers to the others and someone shall be happy to check them.
no help my dude