R1.1 Measuring Enthalpy Changes Flashcards
(12 cards)
Explain the difference between heat and temperature
Heat is the total energy of the molecules of a substance, whereas temperature is a measure of the average energy of the motions of the molecules in a substance
What is enthalpy (H)?
Enthalpy is the total heat content of a substance
What is enthalpy change (ΔH)?
Enthalpy change is the amount of heat released or absorbed in a chemical reaction
What is the heat equation?
q=mc ΔT
What is the standard enthalpy change of a reaction (ΔHo)?
The amount of energy absorbed or released in a chemical reaction under standard conditions
What are the two possibilities for a chemical reaction?
Heat Energy —> Chemical Energy (Temp. of system goes down—endothermic)
Chemical Energy —> Heat Energy (Temp. of system goes up—exothermic)
What is specific heat capacity?
The amount of hest required to raise 1kg of a substance by 1C
What happens to the heat and temperature in an endothermic reaction?
Heat moves from the surroundings to the system; The temperature of the reaction mixture and surroundings decreases as heat is absorbed by the system
What happens to the heat and temperature in an exothermic reaction?
Heat flows from the system to the surroundings; The temperature of the reaction mixture and surroundings increases as heat is released by the system
What does the system of a chemical reaction entail?
The products and reactants (the chemical reaction)
What does the surroundings of a chemical reaction entail?
Everything else outside the system, including the reaction mixture
What is absolute temperature?
The measure of the average kinetic energy of the particles in a substance
