Students are provided with five diagrams of different arrangements of atoms. They select which diagram represents water, graphite, oxygen, and carbon monoxide.
Students are given the formula of two different types of chlorophyll. Students name all the elements present, and how the number of atoms differs between the chlorophylls.
Students are given two equations describing the burning of petrol. Students identify each as either complete or incomplete combustion and then describe two disadvantages of incomplete combustion.
Task: Decide whether described situations are examples of melting or dissolving, provide further examples, and describe what happens when something melts, and when something dissolves. Assessment focus: definitions of melting and dissolving.