100 g of water is heated from 30° C to 50° C. Ignoring the slight expansion of the water, the change in its internal enetgy is (specific heat of water is 4184 J / kg / K )

Question

100 g of water is heated from 30° C to 50° C. Ignoring the slight expansion of the water, the change in its internal enetgy is (specific heat of water is 4184 J / kg / K ) (A) 2.1 kJ (B) 4.2 kJ (C) 8.4 kJ (D) 84 kJ

Tardigrade Admin · Accepted Answer

Q=Δ U+W As W=0 ⇒ Δ U=Q =4184 × (100/1000) × 20 =8368 =8.368 kJ ≈ 8.4 kJ

Q. $100 g$ of water is heated from $3 0^{\circ} C$ to $5 0^{\circ} C$ . Ignoring the slight expansion of the water, the change in its internal enetgy is (specific heat of water is $4184 J / k g / K)$

$2.1 k J$

$4.2 k J$

$8.4 k J$

$84 k J$

$Q = Δ U + W$
As $W = 0$
$\Rightarrow Δ U = Q$
$= 4184 \times \frac{100}{1000} \times 20$
$= 8368$
$= 8.368 k J$
$\approx 8.4 k J$

Q. 100g of water is heated from 30∘C to 50∘C. Ignoring the slight expansion of the water, the change in its internal enetgy is (specific heat of water is 4184J/kg/K)

2.1kJ

4.2kJ

8.4kJ

84kJ