20 g of water (specific heat of water is 4.18 J / g °C) undergoes a temperature change from 25° C to 20° C. How much heat energy moved from the water to the surroundings?

418J

Explanation:

Given parameters:

Mass of water  = 20g

Specific heat capacity of water = 4.18J/g°C

Initial temperature  = 25°C

Final temperature  = 20°C

Unknown:

Amount of heat lost to the surroundings = ?

Solution:

The amount of heat lost to the surrounding is the same as the quantity of heat needed to take down the temperature of the water.

Now, to solve this problem, use the mathematical equation below;

    H = m c (T₂ - T₁)

H is the amount of heat

m is the mass

c is the specific heat capacity

T is the temperature

1 and 2 are initial and final states.

  Now insert the parameters and solve;

     H  = 20 x 4.18 x (20 - 25)

     H  = -418J

The quantity of heat the moved from water to the surrounding is 418J