Compounds that contain the element copper, Cu\text{Cu}Cu, have many uses.
Calculate the mass of one atom of copper.
Give your answer to 3 significant figures.
Copper(II) chloride is an ionic compound made from copper(II) ions, Cu2+\text{Cu}^{2+}Cu2+, and chloride ions, Cl−\text{Cl}^-Cl−.
Construct a balanced ionic equation for the formation of copper(II) chloride.
Copper(II) chloride can conduct electricity when aqueous or molten, but not when solid.
Copper metal can conduct electricity when solid.
Explain why.
Titanium dioxide, TiO2\text{TiO}_2TiO2, is a useful oxide of titanium. The table below shows information about four different titanium dioxide particles.
| Particle | Size of titanium dioxide particles (m) | Cost per gram (£/g) | Purity (%) |
|---|---|---|---|
| A | 3.20 × 10-7 | 0.09 | 96.50 |
| B | 4.15 × 10-9 | 0.55 | 99.95 |
| C | 6.80 × 10-7 | 1.10 | 99.95 |
| D | 2.80 × 10-8 | 2.40 | 99.95 |
Which particles are nanoparticles? Select two options from A, B, C, and D.
A scientist wants to buy titanium dioxide particles for use in sunscreen. A large surface area to volume ratio is important.
Which particle, A, B, C, or D, would be the most suitable for use in sunscreen? Explain your answer.