I need help please with my science homework please I have needed help for hours

Question

1.) 2 NH3 + 3 CuO → 3 Cu + N2 + 3 H2O

In the above equation, how many grams of N2 can be made when 11.8 moles of CuO are consumed?

Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0

Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:

Element	Molar Mass
Hydrogen	1
Nitrogen	14
Copper	63.5
Oxygen	16

2.) For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 14.9 moles of methane, CH4 ?

Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0

Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:

Element	Molar Mass
Hydrogen	1
Carbon	12

please please help explain and solve

Answer 1

The process for answering both of these questions is the same: (NOTE that you only need to concern yourself with the compound whose moles you are given and the compound whose grams you are asked to determine. You can ignore the other compounds in the reaction.)

a. Use the coefficients of the 2 mentioned compounds in the balanced equation to set up a proportion with the given moles of one of them and x moles of the unknown for the other one.

b. Determine the molar mass of the unknown compound.

c. Multiply the molar mass of this compound by the number of moles determined in the proportion to get the number of grams of the compound.

Question 1: This problem is easy to work, but what is not clear is whether the computer expects you to round to the nearest tenth at each step or wait until the end to round. I prefer to keep extra places until the end and then round to the nearest tenth.

3 moles of CuO produces 1 mole of N2. Set up a proportion as follows: (The slash / means divided by.)

(1 mole of N2 ) / (3 moles of CuO) = (x moles of N2) / (11.8 moles of CuO).

Rearrange the equation: x moles of N2 = (1 mole of N2)(11.8 moles of CuO) / (3 moles of CuO)

= 3.93 moles of N2

Since N2 contains 2 atoms of N and a mole of N has a mass of 14 g, then a mole of N2 has a mass of 2 x 14 = 28 g.

To get the number of grams of N, multiply the number of moles of N2 by its molar mass of 28g.

(3.93 moles of N2)(28 g N2 / mole N2) = 110.0 g N2 when rounded to the nearest tenth.

What is not clear from the way the question is worded is whether you must round the 3.93 to the nearest tenth before multiplying it by 28. Since 3.93 rounds to 3.9, 3.9 x 28 = 109.2 g.

Question 2 :

2 moles of hydrogen (H2) produce 1 mole of CH4. Set up a proportion as follows:

(2 moles 2) / (1 mole CH4) = (x moles H2) / (14.9 moles CH4)

Rearranging the equation gives x moles H2 = (2 moles H2)(14.9 moles CH4) / (1 mole CH4)

= 29.8 moles H2

Since 1 mole of H2 contains 2 atoms of H and 1 mole of has a mass of 1, then the molar mass of H2 is 2 x 1 = 2 g/mole

Multiply 29.8 moles H2 by its molar mass

(29.8 moles)( 2 g/mole) = 59.6 g H2.