Module 3: Reactive Chemistry Flashcards
What is a chemical change?
When a new substance is formed and bonds are broken and formed
What is a physical change?
When there is a change in property but no new products are formed
What are four signs of chemical change?
- Colour change
- Significant temperature change
- Formation of precipitate in a solution
- Production of gas/bubbles
What does conservation of atoms mean?
No atoms are created or destroyed, therefore mass of products must equal mass of reactants
What is a synthesis reaction?
Involves forming a compound from elements or from other, usually smaller compounds
What is a decomposition reaction?
Is a reaction in which one reactant is broken down into two or more products
What is thermal decomposition?
When heat is used for decomposition reactions
What is electrolysis?
When electricity is used for decomposition reactions
What is photolysis?
When light energy is used for decomposition reactions
What is a combustion reaction?
It is the combustion of a hydrocarbon and is an oxidation and exothermic reaction
What are the three key elements of combustion?
- Fuel
- Oxygene
- Energy
What is complete combustion?
Combustion which occurs when there is plenty of oxygen
What is produced in complete combustion?
carbon dioxide and water
What is incomplete combustion?
Combustion which occurs when there is limited oxygen
What is produced in incomplete combustion?
carbon monoxide + water
carbon (solid) + water
carbon monoxide + carbon (solid) + water
What is a precipitation reaction?
When an insoluble compound is formed when two clear solutions are mixed
What is a precipitate?
The solid formed in a precipitation reaction
What are spectator ions?
Ions which are not used to form the precipitate and will start aqueous and remain aqueous
What is an ionic equation?
A chemical equation which does not include spectator ions
What does SNAAP stand for?
Sodium
Nitrate
Ammoniam
Acetate
Potassium
What is the equation for acid and base reactions?
Acid + Base –> Salt + Water
What is the equation for acid and carbonate reactions?
Acid + Metal Carbonate –> Salt + Carbon Dioxide + Water
What is the equation for acid and metal reastions?
Acid + Metal –> Salt + Hydrogen Gas
What food did indigenous people detoxifying using chemical reactions?
Cycad fruit
What were the two ways cycads were detoxified?
Leaching - soaking poisons out
Fermentation - leaving the fruit in a moist environment for months
What happens when metal reacts with oxygen?
An electron is transferred from metal atoms to oxygen atoms
What is the formula for the reaction between oxygen and metal?
metal + oxygen –> metal oxide
What happens when metal reacts with water?
Some metals displace hydrogen and hydroxide or metal oxide
When is metal oxide formed when water reacts with metal?
When the metal has a low reactivity such as aluminium zinc or iron and only reacts with steam
When will a reaction between metals and other metallic ions occur?
When the solid metal is more reactive than the metal ions in the solution
Methane
CH4
Ethanol
C2H5OH
