Topic 5 energy changes

Question 1

how can you make an energy change experiment more accurate (measuring temperature)

Answer 1

insulate beaker/polystryene cup
add a lid
stir more
repeat and calculate mean
use digital thermometer

Question 2

what’s endothermic

Answer 2

absorbs energy from surroundings so temp increases

Question 3

what’s exothermic

Answer 3

releases energy into the surroundings in the form of heat
temp of surroundings increases ->

Question 4

examples of exothermic reactions

Answer 4

combustion
oxidation
neutralisation
(self heating cans and hand warmers)

Question 5

endothermic reactions examples

Answer 5

thermal decomposition
citric acid+ sodium hydrogen carbonate (sports injury packs)

Question 6

what is activation energy

Answer 6

minimum energy required to start a reaction
(collide with enough energy)

Question 7

what is conservation of energy

Answer 7

in chemical reactions the amount of e stays the same
E OF REACTANTS = E OF PRODUCTS

Question 8

how do chemical reactions occur

Answer 8

reacting particles collide with enough e (activation e)

Question 10

mash

Answer 10

metal+ acid forms salt+ hydrogen

Question 11

magnesium + hydrochloric acid

Answer 11

mg+ hcl -> MgCl(aq) + H2(g)