you mix 45 ml of .20M KOH in calorimeter. The temperature of both reactions before mixing is 21.5 C. The Cp of the calorimeter was 36 J/K. If the final temperature of the mixture is 23.6 C, what is the enthalpy change per mole of water produced?

THE ENTHALPY CHANGE PER MOLE OF KOH IS 8400 Joules/ mole OF HEAT.

Explanation:

Heat = heat capacity * change in temperature

Heat capacity = 36 J/K

Temperature of the mixture before mixing = 21.5 C

Temperature of mixtire after mixing = 23.6 C

Calculate the change in temperature:

Change in temperature = 23.6 C - 21.5 C = 2.1 C

Heat = 36 * 2.1

Heat = 75.6 J of heat

In essence, 45 ml of 0.20 M of KOH produces 75.8 J of heat

The enthalpy change per mole of water:

It is important t obtain the number of moles involved in the reaction of 45 mL of 0.20 M of KOH

n = C V

n = 0.20 M * 45 *10^-3

n = 0.009 moles

Since number of moles = mass / molar mass

The mass of 45 ml of 0.20 M of KOH is then:

Molar mass = ( 39 + 16 + 1) g/mol = 56 g/mol

Mass = number of moles * molar mass

Mass = 0.009 * 56

Mass = 0.504 g

So therefore 0.504 g of KOH produces 75.6 J of heat

1 mole of KOH will produce x J of heat

1 mole of KOH = 56 g of KOH

0.504 g = 75.6 J

56 g = x J

x J = 56 * 75.6 / 0.504

x J = 8400 J / mole of KOH

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.