chapter 9, energy changes

Question 1

give 2 examples of exothermic reactions

Answer 1

Combustion, making an ice cube

Question 2

give 2 examples of endothermic reactions

Answer 2

Melting ice, evaporation

Question 3

what is a neutralisation reaction?

Answer 3

a neutralisation reaction is the process of mixing an acidic solution and an alkalinr solution

Question 4

why does the temperature increase during an exothermic reaction?

Answer 4

the reaction releases energy, making it exothermic.

Question 5

what do you look for when choosing a fuel?

Answer 5

hoe much energy it releases on burning, what products it produces after burning, how the fuels are produced, what are the gazards of using the fuel

Question 6

what is the combustion product of hyrdrogen?

Answer 6

Water

Question 7

What id the combustion product of ethanol?

Answer 7

carbon dioxide and water

Question 8

What are the different ways fuels are produced?

Answer 8

diesel: decayed animals
Hydrogen: methane (animal waste)
Ethanol: plants (sugar cane)

Question 9

explain ‘H=m x c x △T’

Answer 9

H= energy transferred from water as heat
M= mass of the water
C= heat capacity of the water (4.2 j/g degrees celcius)
△T= temperature change of the water

Question 10

explain why dissolving ammonium nitrate is an endothermic reaction

Answer 10

When you dissolve ammonium nitrate in water it takes in heat from its surroundings. For example when you put ammonium nitrate dissolved with water on top of a block of wood with a drop of water, the ammonium nitrate takes heat from the block of wood, the water turns to ice.