Chapter 8

Question 1

Grid energy storage

Answer 1

batteries store renewable energy for later use

Question 2

supercapacitators

Answer 2

store energy using electrical charge seperation. charge and discharge very quickly. great for short term energy, not long term power

Question 3

Fuel cell

Answer 3

Converts chemical energy (from fuel + 02) directly into electricity.

Question 4

Anode

Answer 4

H₂ → 2H⁺ + 2e⁻

Question 5

Cathode

Answer 5

O₂ + 4H⁺ + 4e⁻ → 2H₂O

Question 6

Overall

Answer 6

2H₂ + O₂ → 2H₂O

Question 7

Toxic metals

Answer 7

(lead, cadmium, lithium) → need proper disposal.

Question 8

what affects battery voltage

Answer 8

type of materials (electrodes) used, the concetration of ions in the electrolyte, temperature, internal resistance

Question 9

What is the function of a salt bridge in a galvanic cell?

Answer 9

It allows ions to flow between half-cells to maintain charge balance.

Question 10

What is the usual oxidation number of oxygen?

Answer 10

-2

Question 11

What is the anode material in an alkaline battery?

Answer 11

zinc

Question 12

What is the cathode material in an alkaline battery?

Answer 12

Manganese dioxide (MnO₂).

Question 13

What is the purpose of grid energy storage?

Answer 13

To store renewable energy (like solar or wind) for later use.

Question 14

How do supercapacitors differ from batteries?

Answer 14

They store energy electrostatically, not chemically.

Question 15

Why are hydrogen fuel cells considered clean energy sources?

Answer 15

They produce electricity with water as the only by-product.

Question 16

Oxidation

Answer 16

when a substance loses electrons

Question 17

reduction

Answer 17

when a substance gains electrons

Question 18

Anode

Answer 18

oxidation

Question 19

cathode

Answer 19

reduction

Question 20

oxidation state

Answer 20

shows how many electrons an atom has gained or lost.

Question 21

Ohm’s Law

Answer 21

V= IxR

Question 22

Voltage

Answer 22

V

Question 23

Current

Answer 23

I

Question 24

Resistance

Answer 24

R

Question 25

Alkaline Battery

Answer 25

disposable battery, not rechargable

Question 26

Lead acid battery

Answer 26

used in car batteries, rechargable

Question 27

Lithium Iron battery

Answer 27

Found in phones, laptops, rechargable, lightweight, high energy density

Question 28

rechargable batteries

Answer 28

can reverse redox reaction during charging

Question 29

What direction do electrons flow in a battery?

Answer 29

From anode → cathode through the external circuit.

Question 30

In a compound, what must the sum of all oxidation numbers equal?

Answer 30

the total charge of the compound or ion

Question 31

What type of battery is commonly used in cars?

Answer 31

Lead-acid battery

Question 32

What are two advantages of lithium-ion batteries?

Answer 32

High energy density and rechargability

Question 33

What makes a battery rechargeable?

Answer 33

The redox reaction can be reversed by applying electrical energy.

Question 34

Name two examples of rechargeable batteries.

Answer 34

Nickel-cadmium (NiCd) and lithium-ion batteries.

Question 35

What is the main fuel used in hydrogen fuel cells?

Answer 35

Hydrogen gas (H2)

Question 36

Hybrid vehicles

Answer 36

combine a gasoline engine with battery power. reduce fuel use and emmisions. use rechargable batteries, produce less pollution

Question 37

What type of reaction powers a battery?

Answer 37

Redox reactions

Question 38

What is the oxidation state of any pure element?

Answer 38

0

Question 39

What is the usual oxidation number of hydrogen?

Answer 39

+1

Question 40

What is the electrolyte in a lead-acid battery?

Answer 40

Sulfuric acid (H₂SO₄).

Question 41

Which type of battery is lightweight, rechargeable, and used in phones and laptops?

Answer 41

Lithium-ion battery

Question 42

What is a main hazard of lithium-ion batteries?

Answer 42

They can overheat or catch on fire if damaged

Question 43

What is the only product of a hydrogen fuel cell?

Answer 43

Water