Chemical Reactions Flashcards
How would you classify a reaction as a chemical change and a physical change?
A chemical change is irreversible and a physical change is reversible.
What are the characteristics of chemical and physical changes?
Physical Changes
- Anything to do with its physical appearance. E.g. brittleness
Chemical Changes
- Anything to do with a chemical reaction.
What is the difference between the physical properties and chemical properties of a substance?
Physical properties - in a physical change, a substance simply changes physical state. E.g. from a solid to a liquid
Chemical properties - chemical changes happen when chemical reactions happen. They involve the formation of new chemical elements or compounds.
What is an oxidation reaction?
A reaction where oxygen bonds with a substance.
What is a chemical reaction where a substance combines with oxygen rapidly giving out energy?
Combustion reaction
Describe the combustion of the element magnesium in oxygen. Include what you would observe and name the product.
Describe the combustion of the element magnesium in oxygen. Include what you would observe and name the product. Additionally state the symbol equation.
- chemical exothermic reaction
- producing magnesium oxide
- intense white flame
- white powder produced (magnesium oxide)
- 2Mg (s) + O2 (g) —> 2MgO (s)
Describe the combustion of the element sulphur in oxygen. Include what you would observe and name the product. Additionally, state the symbol equation.
- chemical, exothermic reaction
- blue flame
- colourless, poisonous gas produced (sulphur oxide)
- S (s) +O2 (g) —> SO2 (g)
Describe the combustion of the element hydrogen in oxygen. Include what you would observe and name the product. Additionally, state the symbol equation.
- chemical, exothermic reaction
- water is produced
- 2H2 (g) + O2 (g) —> 2H2O (g)
Are solutions of metal oxides acid or alkaline?
Alkaline
Are solutions of non-metal oxides acidic or alkaline?
Acidic
What is a fuel?
A substance that when burned in oxygen releases energy.
What is a hydrocarbon?
A compound made up of hydrogen and carbon atoms only.
What is a word equation for the combustion of hydrocarbons.
Methane + oxygen —> carbon dioxide + water
Bob bubbled a gas through limewater and the limewater turned cloudy. What gas was Bob using?
Carbon dioxide
What paper turns from blue to pink when mixed with water?
Cobalt chloride paper
What does cobalt chloride paper do when water is added to it?
Turns from blue to pink
What is the chemical test for water?
Cobalt chloride paper turns from blue to pink
Define thermal decomposition.
The breaking down of a substance through heat.
Do all carbonates decompose through heating?
No
What is the word equation for the thermal decomposition of metal carbonates?
Calcium carbonate —> calcium oxide + carbon dioxide
What is an exothermic reaction?
A reaction in which heat energy is released.
What is an endothermic reaction?
A reaction where heat energy is taken in.
An acid ranges between which numbers on the pH scale?
1-6
