energy changes

Question 1

what is an endothermic reaction?

Answer 1

where energy is taken in from the surroundings so the temeperature cools down

Question 2

what is an exothermic reaction?

Answer 2

when energy is released into the surroundings and the temperature goes up

Question 3

give an example an a reaction that is endothermic

Answer 3

thermal decomposition

Question 4

give an example an a reaction that is exothermic

Answer 4

combustion
neutralisation

Question 5

what is a base?

Answer 5

something that forms an queous solution with a pH of greater that 7

Question 6

what do weak acids do in water?

Answer 6

they dont fully ionise

Question 7

what do strong acids do in water/

Answer 7

they fully ionise to form H+ ions

Question 8

is the ionisation of a weak acid reversible?

Answer 8

yes

Question 9

what is the strength of acids?

Answer 9

how much they ionise in water

Question 10

what is the concentration of an acid?

Answer 10

how much acid is in a certain volume of water
this is different to acid strength

Question 11

what are metal oxides and hydroxides?

Answer 11

alkalis

Question 12

if the mass appears to go down in a chemical reaction then what actually happens?

Answer 12

gas is probaly been produced and escaped to the environment

Question 13

why would the mass appear to go up in a reaction?

Answer 13

the gas reactant is floating around so you can not account for all its mass when it reacts it becomes contained inside the reacrion vessel

Question 14

give an example of everyday exo and endothermic reactions

Answer 14

exo- self heating cans, hamd warmers
endo- cold pack