Consider the reaction 2 nh3 + ch3oh → products. how much nh3 is needed to react exactly with 21 grams of ch3oh?

The NH3 needed to react exactly with 21 grams of CH3OH is calculated as follows

2NH3 + CH3OH = products

find the moles of CH3OH used

moles = mass/molar mass

= 21 grams/32 g/mol = 0.656 moles

from the mole ratio between NH3 to CH3OH which is 2:1 the moles of NH3 is therefore = 0.656 x2/1 = 1.312 moles

mass of NH3 is therefore = moles of NH3 x molar mass of NH3

= 1.312 moles x 17 g/mol = 22.3 grams