Answer:
0.5
Explanation:
Cu Cu2S
2 : 1 ratio
therefore 0.25 moles of Cu2S * (2 moles of Cu/ 1 mole of Cu2S)
=0.5 moles of Cu
Mole ratio of H₂ : O₂ is 2 : 1
∴ if mole of H₂ = 1.67 mol
then mole of O₂ =

⇒ that mole of oxygen needed to react with
H₂ = 0.835 molThe answer is A
Answer:
1.38×10^25 molecules
Explanation:
Applying n= (no. of molcules)/NA
23 = N/6.02×10^23
= 1.38×10^25 molecules