1g of water, of volume 1 cm3 at 100°C, is converted into steam at same temperature under normal atmospheric pressure (≃ ) 1× 105Pa . The volume of steam formed equals 1671 cm3. If the specific latent heat of vaporisation of water is 2256 J/g, the change in internal energy is,

Question

1g of water, of volume 1 cm3 at 100°C, is converted into steam at same temperature under normal atmospheric pressure (≃ ) 1× 105Pa . The volume of steam formed equals 1671 cm3. If the specific latent heat of vaporisation of water is 2256 J/g, the change in internal energy is, (A) 2423 J (B) 2089 J (C) 167 J (D) 2256 J

Tardigrade Admin · Accepted Answer

Q = Δ U + W ⇒ mL = Δ U + P(V2 - V1) ⇒ 1(2256) = Δ U + 1 × 105 (1670 × 10-6) ⇒ Δ U = 2089 J

Q. 1g of water, of volume 1 cm3 at 100°C, is converted into steam at same temperature under normal atmospheric pressure (≃ ) 1×105Pa . The volume of steam formed equals 1671 cm3. If the specific latent heat of vaporisation of water is 2256 J/g, the change in internal energy is,

2423 J

2089 J

167 J

2256 J

Q=ΔU+W ⇒mL=ΔU+P(V2​−V1​) ⇒1(2256)=ΔU+1×105(1670×10−6) ⇒ΔU=2089J

$Q = Δ U + W$
$\Rightarrow m L = Δ U + P (V_{2} - V_{1})$
$\Rightarrow 1 (2256) = Δ U + 1 \times 1 0^{5} (1670 \times 1 0^{- 6})$
$\Rightarrow Δ U = 2089 J$