Ionic substances conduct electricity when molten or aqueous. Which of these statements correctly explains why?
Electrons can move and carry charge.
Ions can move and carry charge.
Isotopes can move and carry charge.
Which of these substances has a molecular covalent structure?
Graphite
Diamond
Methane
Which of the following statements about molecular covalent substances is true?
They have strong covalent bonds between atoms in the molecule.
They have high melting and boiling points due to strong intermolecular attractions.
They conduct electricity as they are charged.
What is an allotrope?
Different forms of the same element in the same physical state.
Different forms of different elements in the same physical state.
Different forms of different elements in different physical states.
In diamond, each carbon atom is joined to how many other carbon atoms?
3
4
5
Why can graphite conduct electricity?
The forces of attraction between each layer are weak.
Delocalised electrons can move and carry charge.
Carbon ions can move and carry charge.
What is the meaning of the term malleable?
A substance that can be drawn out into wires.
A substance that rings like a bell when struck.
A substance than can be hammered into shape.
What percentage gold is 18 carat gold?
75%
85%
100%
Which of the following statements about alloys is false?
Alloys are hard because the different sizes of metal ions mean that layers cannot slide over each other easily.
Alloys are mixtures of two or more elements, one of which must be a metal.
Alloys have non-metallic properties.
Substance X has a high melting and boiling point, doesn't conduct electricity when solid but does conduct electricity when molten and is soluble in water. What structure does substance X have?
Ionic.
Giant covalent.
Metallic.