energy changes

Question 1

what happens to energy in a chemical reaction

Answer 1

it is conserved, the amount of energy at the end of the reaction is the same amount as at the start of the

Question 2

what is an exothermic reaction

Answer 2

a reaction in which energy is transferred to the surroundings so the temperature of the surroundings increases

Question 3

what is an exothermic reaction example

Answer 3

combustion, oxidation reactions and neutralisation

Question 4

what are the everyday uses of exothermic reactions

Answer 4

self heating cans and neutralisation

Question 5

what is an endothermic reaction

Answer 5

a reaction in which energy is transferred from the surroundings so that the temp of the surroundings decrease

Question 6

what is an endothermic reaction example

Answer 6

thermal decomposition and reaction of citric acid and sodium hydrocarbonate

Question 7

what are everyday uses of endothermic reactions

Answer 7

sports injury pack

Question 8

what is activation energy

Answer 8

the minium amount of energy that the particles need to react when the other reacting particles collide with each other

Question 9

what are reaction profiles

Answer 9

a diagram that can be used to show the relative energies of reactants and products, shows the activation energy and overall energy change of a reaction

Question 10

what happens to bonds only during a chemical reaction

Answer 10

energy is supplied to break bonds in the reactants and wnergy is released when bonds in the products are formed

Question 11

how can the overall energy change be calculated

Answer 11

calculate the difference between the sum of the energy needed to break the bonds in the reactants and the sum of the energy released when bonds in the products are formed