The molar heat capacity of water at constant pressure, C, is 75 JK -1 mol -1. When 1.0 KJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is :

Question

The molar heat capacity of water at constant pressure, C, is 75 JK -1 mol -1. When 1.0 KJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is : (A) 6.6 K (B) 1.2 K (C) 2.4 K (D) 4.8 K

Tardigrade Admin · Accepted Answer

Q = 1 kJ = 1000 J m = 100 g = (100 g/18 g mol-1) = 5.55 mol Q = mC . Δ t Δ t = (Q/m.C.) = (1000 J/5.55 mol × 75 JK-1 mol-1) = 2.4 K

Q. The molar heat capacity of water at constant pressure, $C$ , is $75 J K^{- 1} m o l^{- 1}$ . When $1.0 K J$ of heat is supplied to $100 g$ of water which is free to expand, the increase in temperature of water is :

6.6 K

1.2 K

2.4 K

4.8 K

$Q = 1 k J = 1000 J$
$m = 100 g = \frac{100 g}{18 g m o l ^{- 1}} = 5.55 m o l$
$Q = m C .Δ t$
$Δ t = \frac{Q}{m . C .} = \frac{1000 J}{5.55 m o l \times 75 J K ^{- 1} m o l ^{- 1}} = 2.4 K$

Q. The molar heat capacity of water at constant pressure, C, is 75JK−1mol−1. When 1.0KJ of heat is supplied to 100g of water which is free to expand, the increase in temperature of water is :