Question

72g of magnesium reacts with 56 g nitrogen . Calculate number of moles of unreacted reactant

Answer 1

Answer:

mass of magnesium = 72g

molar mass of magnesium = 24

number of moles of magnesium =  72 ÷24 = 3 moles

mass of nitrogen = 56g

molar mass of nitrogen = 14

number of moles of nitrogen = 56 ÷ 14 = 4 moles  

3Mg + 2N =$Mg_{3}$$N_{2}$ (1 mole of product)  

number of moles of unreacted reactant ⇒

(3 moles of Mg +4 moles of N) - (3Mg +2N) = 2 moles of Nitrogen

Explanation: