How many joules are needed to change the temperature of 40 g of water from 33 C to 23 C?

Explanation:

Given parameters:

Mass of water  = 40g

Initial temperature  = 33°C

Final temperature  = 23°C

Specific heat capacity of water  = 4.2J/g°C

Unknown:

Quantity of heat = ?

Solution:

To solve this problem, we use the expression below;

       H  = m c Δt

H is the quantity of heat

m is the mass

c is the specific heat capacity

Δt is the change in temperature

      H  = 40 x 4.2 x (23 - 33) = -1680J

The water will have to lose 1680J of heat to bring it to that final temperature.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

answer; 4 electrons;