Carbon lattices and nanomaterials

Which of the following materials is an example of a 3-D covalent lattice?

• Copper

• Diamond

• Carbon dioxide

• Potassium chloride

The two types of bonding in graphite are

• Covalent and ionic

• Metallic covalent

• Ionic and metallic

• Covalent and dispersion

The term allotropes describes

• Two atoms of the same element with different mass numbers

• Different forms of the same element in which the atoms combine in different ways

• the term for the arrangement/structure of carbon atoms which is formed from combustion of wood or other plant matter

• the process by which a substance goes directly from the solid phase to the gaseous phase, without passing through the liquid phase

Diamond is hard but brittle due to the presence of:

• Directional dispersion forces in 3 dimensions

• directional dipole-dipole forces in 3 dimensions

• Directional hydrogen bonding in 3 dimensions

• Directional covalent bonding in 3 dimensions

What statement is incorrect about graphite

• It conducts electricity

• It can be used as a lubricant

• It is slippery

• It's melting point is 3600 C

Silicon carbide, SiC, has a similar structure to diamond. What type of properties would you expect?

• Hard, good electrical conductor, high melting point

• Hard, good electrical conductor, low melting point

• Soft, good electrical conductor, high melting point

• Hard, poor electrical conductor, high melting point

The difference between graphite and graphene is that:

• Graphite consists of numerous layers of carbon atoms whereas graphene is single layer of carbon atoms

• Graphite consists of multiple layers of carbon atoms whereas graphene is a network lattice of carbon atoms

• Graphite consists of one layer of carbon atoms whereas graphene consists of multiple layers of carbon atoms

• Graphite consists a network of carbon atoms whereas graphene consists of multiple layers of carbon atoms

Which of the following sets of substances are all covalently bonded?

• graphite, mercury, hydrogen bromide and sodium iodide

• fullerenes, diamond, calcium chloride and methane

• zinc nitrate, sulfur dioxide, carbon monoxide and brass

• ammonia, hydrogen chloride, water and silicon dioxide

One difference between ionic and molecular substances is that molecular substances

• melt at higher temperatures than ionic substances.

• do not conduct in the molten state, whereas ionic substances do.

• are insoluble in water, while ionic substances are all water-soluble.

• never form conducting aqueous solutions, while all aqueous solutions of ionic compounds are

  good conductors.

The diagrams below show four possible structures for solid materials.

Which structure best represents a material which has a melting point of –156° and does not conduct

electricity in either the solid, liquid or aqueous states?

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