For the reaction 2HNO3 + Mg(OH)2 → Mg(NO3) 2 + 2H2O, how many grams of magnesium nitrate are produced from 3 grams of nitric acid, HNO3 ?

Question

For the reaction 2HNO₃ + Mg(OH)₂ → Mg(NO₃) ₂ + 2H₂O, how many grams of magnesium nitrate are produced from 3 grams of nitric acid, HNO₃ ?

Round your answer to the nearest tenth. Do not round your answers until the last step of the problem. If you do, the computer might mark your answer incorrect and you will be asked to complete your second trial for this assessment.

Use the following molar masses:

Element	Molar Mass
Hydrogen	1
Magnesium	24
Nitrogen	14
Oxygen	16

Answer 1

Assuming magnesium hydroxide is present in excess and nitric acid is provided as a pure chemical ( not as a solution):

Conceptual map: g of HNO₃ —> mole of HNO_{3 —>} mole of Mg(NO₃)₂ —> g of Mg(NO₃)₂

3 g HNO₃ * 1mole HNO₃/ 63 g HNO₃ * 1 mole Mg(NO₃)₂/ 2 moles of HNO_{3 *} 148 g Mg(NO₃)₂ /1 mole of Mg(NO₃)₂. = 3.52 g ( round it off to 4 grams, with 1 sig. fig.)