Question

How much heat is necessary to increase temperature of 4 kg water from 20 degree Celsius to 80 degree Celsius?

Answer 1

Answer:

2.4 × 10⁵ cal

Explanation:

Step 1: Given data

• Mass of water (m): 4 kg

• Initial temperature: 20°C

• Final temperature: 80°C

• Specific heat capacity of water (c): 1 cal/g.°C

Step 2: Convert the mass to grams

We will use the relationship 1 kg = 1,000 g.

$4kg \times \frac{1,000g}{1kg} = 4,000 g$

Step 3: Calculate the change in the temperature

$\Delta T = T_f - T_i = 80 \° C - 20 \° C = 60 \° C$

Step 4: Calculate the heat required (Q)

We will use the following expression.

$Q = c \times m \times \Delta T = \frac{1cal}{g. \° C} \times 4,000 g \times 60 \° C = 2.4 \times 10^{5} cal$