Combustion & Corrosion Flashcards
Endothermic reactions
- a chemical reaction that absorbs energy: eg when a cold pack is applied on an injury, absorbing the energy
- in an endothermic reaction the products have more energy than the reactants.
Exothermic reaction
- a chemical reaction the releases energy: eg a gas stove which has a blue flame releasing the energy in heat or, a series of bush fires as it releases huge amounts of heat and light.
- in an exothermic reaction the reactants have more energy than the products.
Reactants.
Substances/chemicals that take part in a chemical reaction
Products
Are substances/chemicals that are formed by the chemical reaction
Photosynthesis
- a reaction the green plants use to form glucose (sugar)
- this reaction absorbs energy from sunlight, endothermic reaction
Combustion reactions
- are examples of exothermic reactions
- oxygen gas is required for combustion to occur. Meaning combustion occurs when something reacts with oxygen
Incomplete combustion
- occurs when oxygen is restricted and other reactions occur
- these are known as dirty as they produce carbon which is left behind as soot, charcoal or smoke. They also produce the poisonous gas carbon monoxide (fire produces these substances)
Complete combustion
- complete combustion is when oxygen is not restricted and produces carbon dioxide and carbon dioxide which are know as clean reactions
Corrosion
The breakdown of metals due to their reaction with other chemicals to form other compounds. An example would be rust
Rust
When iron or steel slowly reacts with water and oxygen and corrodes into rust aka hydrated iron oxide
Verdigris
A green coating of cooper hydroxide that is produced when copper reacts with moisture, carbon dioxide and oxygen in the atmosphere
Tarnish
A black coating of silver sulfate that is produced when silver reacts Sulfur in the atmosphere
How is verdigris formed
When copper corrodes by reacting with gases in the air
How is tarnished formed
When pure silver reacts with Sulfur creates black coating
What is flaky and easy to dislodge
Rust
What is aluminium oxide
Is a fine layer of dull grey which appears on the surface of metals when aluminium reacts with the air
Anodising
A way of protecting aluminium from corrosion, by deliberately creating a layer of aluminium oxide over it
Hydrocarbons
Highly combustible chemicals for example petrol
Law of conservation of mass
When atoms are not created or destroyed in a chemical reaction as they can only be rearranged
Safety flame
Incomplete combustion as it received no oxygen gas
Blue flame
Complete combustion as it receives oxygen gas
Examples on endothermic reactions
- photosynthesis
- sherbet tingles in your mouth
- a chemical cold pack as it cools sore muscles
Examples of exothermic reactions
- a series of bushfires
- aerobic respiration releases energy for use in cells
- magnesium burns in oxygen releasing light
Similarities of exothermic and endothermic reactions?
- they both the form of heat as their energy
- they are both a type of chemical reaction
- they both need two substances to combine to make the certain reaction
Differences of exothermic and endothermic reactions
- exothermic reaction lets of energy whereas endothermic absorbs energy
Combustion of fossil fuels examples
What the produce and products
- buses burners
- gas stoves
- water heaters
Produce a hot blue flame by burning methane or ethane gas in oxygen which produce hydrocarbons
Indications of incomplete combustion
Carbon in the atmosphere as soot charcoal and smoke
Carbon monoxide poisonous gas
Explain respiration
It gives you energy. The reaction needs glucose from food and oxygen from your body. You breathe out its product carbon dioxide
Exothermic reaction
Combustion reaction that do not produce carbon dioxide and water
When magnesium and oxygen react they form magnesium oxide
Examples of oxidation
Corrosion
Similarities of corrosion and rust ion
- both involve the elements of metal in the reactions
Difference of corrosion and rusting
- rusting is a type of corrosion
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