Question

Calculate the mass of the following:

i 3 moles of ammonia

ii 4.5 moles of methane

iii 0.2 moles of calcium carbonate

iv 1.4 moles of magnesium hydroxide.

Answer 1

Answer:

Hope it helps you

Answer 2

Answer:

i We know that No. of moles=Given weight/Molar mass.

Then mass of ammonia NH3=

1×14+1×3=14+3=17g.

Therefore, 3=x/17

=17×3

=51g.

ii Similarly Molar mass ofCH4=1×12+1×4

=12+4=16g.

Therefore, 4.5=x/16

x=16×4.5

=72g.

iii CaCO3=40+12+16×3=100g.

Therefore ,0.2=x/100

x=20g.

iv Mg(OH)2=24+2×16+2×1

= 58g.

Therefore, 1.4=x/58

x=81.2g.