State the volume occupied by 40 gm of methane at STP

Mole Concept (10)

(i) State the volume occupied by 40 gm of methane at STP, if its vapour density (V.D.) is 8.

(ii) Calculate the number of moles present in 160 gm of NaOH. [Atomic Mass: Na = 23, H = 1, O = 16]

Answer

(i) 16 g of CH₄ occupy = 22.4 L at STP

∴ 40 g of CH₄ occupy = (22.4 x 40)/16 L

= 56 L or 56000 mL

(ii) Number of moles of NaOH = weight in grams / molecular weight

= 160/40

= 4 moles

• Exam Year: 2020