Question

3 Cu + 8HNO3 --> 3 Cu(NO3)2 + 2 NO + 4 H2O

In the above equation how many moles of water can be made when 110.2 grams of HNO3 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

Answer 1

First, we need to calculate the number of moles of HNO3 used in the reaction:

• mass of HNO3 = 110.2 g

• molar mass of HNO3 = 1(1) + 14(1) + 16(3) = 1 + 14 + 48 = 63 g/mol

number of moles of HNO3 = mass of HNO3 / molar mass of HNO3

number of moles of HNO3 = 110.2 g / 63 g/mol

number of moles of HNO3 = 1.75 mol

• According to the balanced chemical equation, 4 moles of water are produced for every 8 moles of HNO3 consumed. Therefore, we can use a proportion to find the number of moles of water produced:

8 mol HNO3 : 4 mol H2O = 1.75 mol HNO3 : x mol H2O

• x = 0.875 mol H2O

Rounding to one decimal place, we get:

• x = 0.9 mol H2O

Therefore, when 110.2 grams of HNO3 are consumed, approximately 0.9 moles of water can be made.