c7

Question 1

difference between primary and secondary cellls?

Answer 1

only secondary cells can be recharged

Question 2

2 adv and dis of hydrogen fuel cells?

Answer 2

+refilled quickly
+no pollutants produced
-hydrogen difficult to store
-hydrogen flammable

Question 3

electrical cell?

Answer 3

contains chemicals that produce electricity

Question 4

battery

Answer 4

two or more cells connected in series to provide a greater potential difference

Question 5

elctrode

Answer 5

A conductor through which electricity enters or leaves an object substance or region

Question 6

energy needed to seperate two chemically bonded atoms?

Answer 6

bond energy

Question 7

bond breaking?
bond making?

Answer 7

breaking- endothermic
making- exothermic

Question 8

energy needed to break bond same as?

Answer 8

energy needed to make bond

Question 9

what cuases current to flow in a chemical cell?

Answer 9

more reactive metal gives less reactive metal electrons

Question 10

3 factors affecting pd in a chemical cell

Answer 10

type of electrode
concentration of electrolyte
temperature

Question 11

adv and dis of fossil fuels

Answer 11

+high energy density
-CO2 produced

Question 12

adv and dis of battery (in car)

Answer 12

+low cost per mile
-charging time

Question 13

where is hydrogen attracted to, what does it release and what ion does it form?

Answer 13

cathode (negative), releases electrons, produces H+ ions

Question 14

what is oxidised and reduced in hydrogen fuel cells?

Answer 14

hydrogen- oxidised
oxygen- reduced

Question 15

equ at anode for hydrogen fuel cell?

Answer 15

O2+2H2O+4e- forms 4OH-

Question 16

equ at catode for hydrogen fuel cell?

Answer 16

H2+2OH- forms 2H2O+2e-

Question 17

adv and dis of fuel cells? (cars)

Answer 17

+no pollution from vehicle
-expensive

Question 18

equ for formation of water?

Answer 18

4H+ + 4e- forms 2H20