Robert S. answered • 05/03/21

Dr Bob Loves Science (especially chemistry and math)

Hello, Ethan,

* 1.) *For the reaction C + 2H2 → CH4, how many grams of hydrogen are required to produce 17 moles of methane, CH4 ?

The balanced equation tells us that it takes 2 moles of H_{2} to make 1 mole of CH_{4}. That's a molar ratio of (2 hyrogen/1 methane) . Since we want 17 moles of methane, we'll need twice that number of moles of hydrogen, 34 moles. Multiply 34 moles H_{2} time the molar mass of H_{2} (2 grams/mole) to find that it will take 68 grams of hydrogen to produce 17 moles of methane.

* 2.) *3 Cu + 8HNO3 → 3 Cu(NO3)2 + 2 NO + 4 H2O

**In the above equation, how many grams of water can be made when 1.4 moles of HNO3** **are consumed?**

Using the same logic, we see that the molar ratio of HNO_{3},nitric acid, to water is 8/4. We make 4 moles of water for every 8 moles of nitric acid. So we should multiply the moles nitric acid by (1/2) to get moles H_{2}O. That means we only get 0.7 moles of water. Whoopee. Multiply moles water by it's molar mass to arrive at a water mass of 12.6 grams.

Bob