energetics

Question 1

what is meant by the term enthalpy change

Answer 1

the change of heat

Question 2

how is enthalpy change represented?

Answer 2

delta H

Question 3

what are the standard conditions for enthalpy change to be measured under

Answer 3

100kPa pressure and

298 K temperature

Question 4

what is the direction of the enthalpy change when energy is taken in. explain

Answer 4

when energy is taken in from the surroundings, it is an endothermic reaction. this means that the nthalpy change will be positive

Question 5

what is the overall enthalpy change formula

Answer 5

energy to break bonds + energy to make bonds

Question 6

what is the enthalpy change of a reaction

Answer 6

the enthalpy change when quantities of substances in standard states react completely under standard conditions

Question 7

what is the definition of the enthalpy change of formation`

Answer 7

the enthalpy change when one mole of a substance is produced from its elements under standard contitions

Question 8

definition of enthalpy change of combustion

Answer 8

the enthalpy change when one mole of a substance is burned completely in oxygen under standard conditions

Question 9

hats the definition of enthalpy change of neutralisation

Answer 9

the enthalpy change when solutions of acid and alkali react together under standard conditions to produce one mole of water

Question 10

calorimetry definition

Answer 10

an experimental methd to find change by measuring temperature change over time. when recorded and plotted a graph, data can be extrapolated to give an accurate value for the change in temperature