A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature according to the reaction equation below. 

An analysis of the mixture at equilibrium revealed 2.1 mol N₂, 2.8 mol H₂ and 1.8 mol NH₃ in a 1.5 L container. How many moles of H₂ were present at the beginning of the reaction?

Please provide your answer with 2 significant figures.

'n Mengsel van stikstof en waterstof word toegelaat om teen 'n gegewe temperatuur tot ewewig te kom volgens die reaksievergelyking hieronder. 

'n Analise van die mengsel by ewewig toon 2.1 mol N₂, 2.8 mol H₂ en 1.8 mol NH₃ in 'n 1.5 L houer. Hoeveel mol H₂ was aan die begin van die reaksie teenwoordig? 

Gee asb jou antwoord met 2 beduidende syfers.