Chemistry 1.5 Demonstrate understanding of chemical reactions
Science 1.8 Investigate selected chemical reactions
This achievement standard involves demonstrating understanding of chemical reactions by classifying selected reactions and predicting precipitates.
This achievement standard involves carrying out practical activities to classify chemical reactions using observations and equations.
Achievement
Demonstrate understanding involves describing, identifying, naming, drawing, giving an account of and classifying reactions. It also involves using solubility rules to
predict solubility. This requires the use of chemistry vocabulary, symbols and conventions including names, formulae and completing word equations.
Merit
Demonstrate detailed understanding requires making and explaining links between observations or equations and the classification of reactions. It also involves predicting precipitation. This requires explanations that use chemistry vocabulary, symbols and conventions including names, formulae and writing word equations or completing given symbol equations.
Excellence
Demonstrate comprehensive understanding will typically involve elaborating, justifying, relating, evaluating, comparing and contrasting, or analysing links between the classification of reactions, observations and equations, and the formation of precipitates and solubility rules. This requires the consistent use of chemistry vocabulary, symbols and conventions including writing balanced symbol equations.
Achievement
Investigate involves carrying out a range of chemical reactions and recording observations and classifying reactions. It will also typically involve describing, gathering, processing, interpreting, identifying, and giving an account of selected chemical reactions and using solubility rules to determine solubility. It requires the use of chemistry vocabulary, symbols and conventions including names, formulae and writing word equations.
Merit
Investigate in detail will involve making links between the classification of chemical reactions derived from experimental observations and / or equations and predicting the formation of a precipitate using solubility rules. This requires explanations that use chemistry vocabulary, symbols and conventions including names, formulae and completing symbol equations.
Excellence
Investigate comprehensively typically involves elaborating, justifying, relating, evaluating, comparing and contrasting, or analysing the links between the classification of reactions, observations and equations and the formation of precipitates and solubility rules. This requires explanations that consistently use chemistry vocabulary, symbols and conventions including writing balanced symbol equations.
Chemical reactions will be selected from:
· Combination reactions. These are limited to reactions of elements with other elements.

· Exchange/precipitation reactions limited to the formation of:
- chlorides and iodides of silver and lead
- sulfates of calcium, barium and lead
- hydroxides of copper, iron(II), iron(III), calcium, barium and magnesium
- carbonates of copper, iron(II), iron(III), calcium, barium, magnesium
- zinc, lead and aluminium ions.

· Decomposition reactions. These are limited to thermal decomposition of hydroxides, carbonates and hydrogen carbonates and catalytic decomposition of hydrogen peroxide.
· Displacement reactions. These are limited to the displacement of metal ions in solution by other metals.

Chemical reactions will be selected from:
· Combination reactions. These are limited to simple reactions of elements with other elements (such as magnesium or sulfur with oxygen, iron with sulfur etc).
· Exchange reactions. These are limited to precipitation reactions such as the
formation of:
- chlorides of silver and lead.
- sulfates of barium and lead.
- hydroxides of copper, iron(II), iron(III), calcium, and magnesium.
- carbonates of copper, iron(II), iron(III), zinc, aluminium, calcium, and magnesium ions.
· Decomposition reactions. These are limited to thermal decomposition of carbonates and hydrogen carbonates.
· Displacement reactions. These are limited to the displacement of metal ions in solution by other metals.