chemical reactions core questions

Question 1

define reactants

Answer 1

substances that react together

Question 2

define products

Answer 2

a substance made in a reaction

Question 3

what are common signs of a chemical reaction

Answer 3

temperature change
colour change
change of state
emitting fumes

Question 4

what is a displacement reaction

Answer 4

when a more reactive element takes the place in a compound of a less reactive element

Question 5

what does the suffix ide mean

Answer 5

only that element present e.g. chloride or oxide

Question 6

what is the reactivity series

Answer 6

list of chemicals (mainly metals) in order of reactivity

Question 7

which metals do not react with acids

Answer 7

copper
silver
gold
platinum
as they are less reactive than hydrogen

Question 8

what is thermal decomposition

Answer 8

breaking down a substance using heat

Question 9

what is a combustion reaction

Answer 9

when a fuel reacts with oxygen (heat and light are produced

Question 10

what is an endothermic reaction

Answer 10

when energy is taken in from the surroundings (normally results in temp going down)

Question 11

what is an exothermic reaction

Answer 11

when energy is released into the surroundings (normally results in temp increasing)

Question 12

what is a catalyst

Answer 12

a substance that speeds up a chemical reaction without being used up

Question 13

what does biodegradable mean

Answer 13

something that decomposes(broken down) by bacteria

Question 14

what is the general equation for complete combustion

Answer 14

fuel(e.g.propane) + oxygen
-> carbon dioxide + water

Question 15

what are some examples of a physical change

Answer 15

change of state (melting, boiling, evaporating)
mixing
dissolving

Question 16

what is the difference between chemical and physical reactions

Answer 16

chemical reactions are normally irreversible and change the chemical structure

physical reactions are normally reversible and are normally just a state or physical change