Thermochemistry and Calorimetry Concepts

The video tutorial explains how to calculate the enthalpy of solution for lithium perchlorate using a coffee-cup calorimeter. It involves dissolving 85.0 grams of lithium perchlorate in 375.0 grams of water, resulting in a temperature change from 20.18°C to 31.21°C. The tutorial covers calculating the heat absorbed by the calorimeter, understanding the exothermic nature of the dissolving process, and converting the energy to kilojoules per mole. The final enthalpy of solution is determined to be -26.5 kJ/mol.

What is the initial temperature of the water in the calorimeter?

• 25.00 degrees Celsius

• 20.18 degrees Celsius

• 31.21 degrees Celsius

• 15.00 degrees Celsius

What is the purpose of using a coffee-cup calorimeter in this experiment?

• To find the density of lithium perchlorate

• To determine the boiling point of water

• To calculate the enthalpy of solution

• To measure the mass of the solution

What is the total mass of the solution in the calorimeter?

• 85.0 grams

• 375.0 grams

• 500.0 grams

• 460.0 grams

How much heat is absorbed by the calorimeter's contents?

• 21,208 joules

• 15,000 joules

• 30,000 joules

• 10,000 joules

Why is the dissolving process considered exothermic?

• Because it absorbs heat from the surroundings

• Because it requires energy input to dissolve

• Because it releases thermal energy, increasing the temperature

• Because it decreases the temperature of the solution

What is the sign of the energy released by the dissolving process?

• Negative

• Positive

• Undefined

• Zero

What is the heat released per 85.0 grams of lithium perchlorate?

• 15,000 joules

• 21,208 joules

• -15,000 joules

• -21,208 joules

How do you convert joules to kilojoules?

• Divide by 1000

• Multiply by 1000

• Subtract 1000

• Add 1000

What is the molar enthalpy of solution for lithium perchlorate?

• -26.5 kilojoules per mole

• 26.5 kilojoules per mole

• -21.5 kilojoules per mole

• 21.5 kilojoules per mole