Chemical reactions Flashcards
(97 cards)
1
Q
In a chemical reaction are there more atoms
A
In a chemical reaction, atoms are rearranged but the number of atoms don’t change
2
Q
How can you tell if there is a chemical reaction
A
Temperature rise, fizzing or bubbles of gas , colour change, smell and sound and flames
3
Q
Is water and tea a chemical or physical change
A
Physical because dissolving is not a chemical reaction.
4
Q
What is ethanoic acid
A
Vinegar
5
Q
What is sodium bicarbonate
A
Baking soda
6
Q
What does vinegar and baking soda make
A
Carbon dioxide
7
Q
What is a physical reaction
A
They are reactions that do not make new chemicals. Examples are boiling, melting and freezing. It is usually reversible
8
Q
What is a chemical reaction
A
Bonds between atoms are broken and made to make new substances
9
Q
What is a dioxide
A
A conpound with 2 oxygen atoms
10
Q
What is a monoxide
A
A compound with one oxygen element
11
Q
What is an oxide
A
An element that reacted with oxygen
12
Q
Scientific name for burning
A
Combustion
13
Q
What is needed for a fire (fire triangle)
A
Heat, oxygen and a fuel
14
Q
What is it called when oxygen is added to a reaction
A
Oxidation
15
Q
What is it called when oxygen is removed from an equation
A
Reduction
16
Q
What type of reaction is combustion
A
Oxidisation because a fuel had to have reacted with oxygen to release energy.
17
Q
Scientific name for rust
A
Iron oxide
18
Q
What do the letters in brackets mean after a formula (state symbols)
A
(s) is solid, l for liquid, g for gas and aq for aqueous solution (dissolves in water)
19
Q
What happens when magnesium reacts with oxygen
A
It creates a bright light which we can protect our eyes from by using a welding mask
20
Q
What does a catalyst do
A
Speed up the rate of reaction
21
Q
What happens when you leave hydrogen peroxide at room temperature, what type of reaction is it and is it slow or quick
A
It turns to water and oxygen and it is a decomposition reaction because it breaks down. It is a slow reaction but you can use a catalyst to speed it up
22
Q
What type of catalysts are enzymes
A
Enzymes are natural biological catalysts
23
Q
What happens to the catalyst when it is added to a reaction
A
It is not used up or chemically changed (mass is the same)
24
Q
What is a common use for catalysts
A
Digestive system and the exhaust system in a car
25
What is an exothermic reaction
When energy is transferred to the surroundings and usually feels hot
26
What is an endothermic reaction
When energy is taken in from the surroundings and usually feels cold
27
Formula for combustion
Fuel + oxygen-> carbon dioxide + water + energy
28
What gas does a Bunsen Burner use
Methane (CH4)
29
What is a bad thing about doing combustion practicals in an open and uninsulated area
Not all the heat will go directly where you want it to and it will go to the surroundings
30
When can we use exothermic and endothermic reactions realistically
Exothermic- hand warmers, fires and respiration
Endothermic- thermal decomposition, melting ice cube (gases have more energy than solids), photosynthesis
31
What is thermal decomposition and is it exothermic or endothermic
Breaking down a compound into its elements or simpler compounds using a high temperature. It is endothermic.
32
What insulates reactions
Polystyrene foam cup
33
What do you call the odd result in a practical
Anomaly or outlier
34
What are reactants and products in a reaction
Reactants are the substances that react together and products are the substances formed
35
What words are not written in word equations
Words like powder ,solution or gas
36
What is the symbol equation for carbonate
CO3
37
What is oxygen as a symbol in the air
O2 because it is a molecule
38
What does acid and base make
Salt and water
39
What do metals and acids make
Salt and hydrogen
40
What do acids and metal carbonates make
salt+ carbon dioxide + water
41
What do you call the little numbers next to elements
Subscripts
42
How to balance an equation
What goes in must go out so the same atoms must be there but they can be rearranged with numbers in front.
43
What is the Law of Conservation of Mass
During chemical reactions or a change of state, no atoms are created or destroyed. The total mass stays the same (mass of reactants= mass of products)
44
If a log is burnt, will the ash of it weight the same as the log and oxygen
No because carbon dioxide and oxygen would have went into the atmosphere but if you gathered those gases it would still weigh the same.
45
Symbol equation for butane
C4H10
46
What is the only product when hydrogen burns
Water
47
What is a fuel
A substance which can be burned to release energy
48
How much reactants and products are in thermal decomposition reactions
One reactant because it is just a compound being heated. There are always 2 or more products because the compound is being broken down
49
Why does ethanoic acid and sodium bicarbonate set out a candle
It produces carbon dioxide which displaces the oxygen to fuel the fire.
50
Are combustion reactions reversible
No they are irreversible
51
Scientific name for fizzing
Effervescence
52
If a reaction tested alcohols to see which was more efficient in heating to 30 degrees, would you want the alcohol that released the least or most mass
The one that released the least amount of mass would be more efficient because it used less energy but still heated it to the same point.
53
What is an element
Substance that consists of one type of atom and in the periodic table
54
What is a compound
A substance made from more than one type of element and they are chemically bonded together
55
What is a diatomic molecule and name an example
A diatomic molecule is a molecule that has two elements, same or different. An example is oxygen.
56
What do you call diatomic molecules with the same element
A homonuclear diatomic molecule
57
What do you call diatomic molecules with different elements
A heteronuclear diatomic element
58
What does it mean for a metal to be found ‘native’
Pure unreactive form
59
Why can we not find most metals in their pure form but we can find gold and silver in their pure form
Gold and silver are unreactive metals so they will be displaced if other substances come into contact with it and left in pure form. However, if reactive metals came into contact with other substances, they would displace another metal and become a compound.
60
What happens to cobalt chloride paper/ anhydrous copper sulfate if exposed to water
The paper will turn pink and the sulfate will go from white to blue
61
What hazard is represented by the symbol of a chemical in a test tube being poured on a hand
Corrosion
62
What hazard is represented by the symbol of a fish and tree and explain it
Environment hazard like pouring chemicals down the sink can harm marine life (water pollution)
63
What hazard is represented by the symbol of a circle in half with arrows pointing outwards
Explosive
64
What hazard is represented by the symbol of a person with arrows pointing out a circle in the centre of their chest
Health hazard
65
What safety precautions can you take
Wearying safety goggles, wearing gloves, wearing a lab coat and tying back hair and tucking away loose clothing
66
What name is given to a reaction where hydrogen ions react with hydrogen ions to make water
Neutralisation
67
Oxidation is the … of electrons. Reduction is the … of electrons
First gap is loss and second is gain
68
There are metals in a room and oxygen so why aren’t they reacting
The metals are already bound to something and not pure metals or you need catalysts
69
What is a metal carbonate
A compound that contains metal, carbon and oxygen
70
How do you stop a fire
Remove a side of the fire triangle
71
What extinguisher to use on a wood fire and why
A water extinguisher because it removes the heat aspect by extreme cooling
72
What extinguisher to use on an electrical fire and why
A CO2 extinguisher because it removes the oxygen aspect by displacing it
73
What extinguisher (or alternative) to use on a chip pan fire and why
A wet chemical extinguisher because it removes the heat aspect.An alternative could be a fire blanket but not water as the fire will spit it out.
74
What extinguisher to use on a car fire and why
An ABC dry powder extinguisher because it removes the oxygen aspect by forming a barrier between the fuel and oxygen source.
75
What do foam extinguishers do
They work by a build up of foam on the surface, meaning oxygen can’t enter and it cools the fuel
76
If a candle was lit in a big or small jar which jar would take longest for the candle to go out and why
It would take longest for the bigger jar’s candle to go out because it had the most oxygen, one of the sides of the fire triangle
77
What does hydrogen do when near a burning splint
Make a pop sound
78
What is the thermal energy store in a fire
Flame
79
Does breaking bonds release or require energy
Releases energy
80
Does making bonds release or require energy
Making bonds requires energy
81
What is a catalytic converter
A part of a car between the engine and the exhaust pipe that converts harmful substances made in the engine into less harmful ones
82
What does conserved mean in a reaction
The quantity if something doesn’t change after a process takes place
83
What is a chemical bond
The force that holds atoms together in molecules
84
What is an example of an experiment to test for the gas produced during thermal decomposition of carbonates
A Bunsen burner heating copper carbonate in a test tube releases carbon dioxide. We can test that by placing a tube leading to a test tube of limewater in the test tube containing copper carbonate. This will result in the limewater going cloudy
85
What is decomposition
A chemical reaction in which a compound breaks down to form more than one product
86
What is an energy level diagram
A diagram showing the relative energies of the reactants and products. It shows whether a reaction is endothermic or exothermic because if the energy rose, the reaction would be endothermic but if the energy decreased, it is exothermic
87
What is a fossil fuel
A fuel made from the remains of animals and plants that died millions of years ago
88
Name 5 fuels used in combustion
Propane, butane, methane, fossil fuels and natural gas
89
What are renewable and non renewable resources
Renewable- a fuel that can be easily replaced within a short time frame
Non-renewable- energy resources that have a limited supply and cannot be replaced within a short timeframe
90
How can you know if oxygen is present
Have a glowing splint and put it into a test tube and if oxygen is present, the glowing splint will relight snd burn brightly
91
When balancing equations what cant you do
Change the little numbers only add big ones in front, and these have to be whole numbers
92
Do exothermic reactions break or make bonds
Make bonds because it releases energy
93
Do endothermic reactions make or break bonds
Break bonds because it requires energy
94
Is combustion endothermic or exothermic
Exothermic
95
Combustion symbol formula
CH4 + O2 —> CO2+ H2O
96
How do catalysts speed up a chemical reaction
They speed up a chemical reaction by lowering the amount if energy you need to get one going
97
When are catalysts used in industry
Gasoline, fertilisers and cooking
