• Data

Mass of copper (CU) = 20g
Molar volume at STP = 22.4dm3/mole

i. The number of mole of CuO
ii. Volume of ammonia gas used
iii. The mass of copper formed

The chemical equation for the reaction
3CUO(s) + 2NH3(s) 3Cu(s) + N2(s) + 3H2O(l)
3 moles: 2 moles: 1 mole: 3 moles
• A. To calculate the number of mole CuO

Mole = mass / Molar mass of CuO
= 20g / 80g/mole
= 0.25 mole

0.25 mole of copper (II) Oxide was reacted with ammonia
• B. To calculate the volume of ammonia

From the equivalent between CuO and NH3
3 moles of CUO Ξ 2moles of NH3
0.25 mole of CuO Ξ ?? of NH3

= (0.25 mole × 2 moles) / 3 moles
= 0.167 mole of NH3

To convert 0.167 mole into volume
Mole = volume / Molar volume
Volume = mole × molar volume
= 0.167 mole × 22.4dm3/mole
= 3.73dm3

73dm3 of ammonia was reacted with CuO
• C. To calculate the mass of Cu formed

From mole equivalent between CuO and Cu 3 moles of CuO Ξ 3 moles of Cu
0.25 moles of CuO Ξ ?? of Cu
= (0.25 moles × 3 moles) / 3
= 0.25moles
O.25 moles of Cu was formed.

To convert 0.25 mole into mass
Mass = mole × molar mass
= 0.25 mole × 64
= 16g
16g of coper (Cu) was formed