Bulk & Surface Properties of Matter Including Nanoparticles Practice Questions

Question 1

4 marks

Nanoparticles are particles with diameters between about 1 nm and 100 nm.

(a)

A nanoparticle of gold has a diameter of 40 nm.

40 nm expressed in metres is

A $4 \times 10^{-6}$ m
B $4 \times 10^{-7}$ m
C $4 \times 10^{-8}$ m
D $4 \times 10^{-9}$ m

/ 1

(b)

A particle of titanium(IV) oxide has a diameter of $2.5 \times 10^{-7}$ m.

Deduce whether or not this particle is a nanoparticle.

/ 2

(c)

An oxygen molecule has a diameter of about $0.2$ nm.

Calculate how many times larger the diameter of the 40 nm gold nanoparticle is than the diameter of an oxygen molecule.

/ 1

Question 2

3 marks

The table gives information about four materials used to make kitchen equipment.

Property	glass	clay ceramic	poly(propene)	aluminium
density in g/cm³	2.5	2.3	0.90	2.7
melting point in °C	1400	1600	160	660
thermal conductivity in W/m K	1.0	1.5	0.2	240
brittle	yes	yes	no	no

(a)

State which material has the lowest density.

/ 1

(b)

Give one reason, using data from the table, why aluminium is used for the base of a saucepan.

/ 1

(c)

Give one reason, using data from the table, why poly(propene) rather than clay ceramic is used for the handle of a saucepan.

/ 1

Question 3

5 marks

The diagram shows a solid cube of copper with sides of length 3 cm.

(a)

Calculate the total surface area of the cube.

/ 2

(b)

Calculate the surface area to volume ratio of the cube.

/ 2

(c)

State what happens to the surface area to volume ratio of a cube of copper as the length of its sides decreases.

/ 1

Question 0

4 marks

Nanoparticles of silver are used in some wound dressings because silver kills bacteria.

Assume that the silver nanoparticles are cubes with sides of length 20 nm.

(a)

Show that the surface area to volume ratio of one of these nanoparticles is $0.3$ nm⁻¹.

/ 2

(b)

A second sample of silver contains cubes with sides of length 200 nm. These have a surface area to volume ratio of $0.03$ nm⁻¹.

Explain why a 1 g sample of the 20 nm particles kills bacteria more quickly than a 1 g sample of the 200 nm particles.

/ 2

Question 0

4 marks

The table gives information about two sunscreens, both of which contain zinc oxide.

Sunscreen	diameter of zinc oxide particles in nm	percentage of UV light blocked	appearance on the skin
A	200	92	white
B	30	98	clear

(a)

State which sunscreen contains nanoparticulate zinc oxide. Give a reason for your answer.

/ 1

(b)

Explain, using the data in the table, why many people choose sunscreen B rather than sunscreen A.

/ 3

Question 0

4 marks

Nanoparticles of silver are added to the fibres of sports socks. The silver kills the bacteria that cause unpleasant smells.

(a)

Explain one possible risk to a person who wears socks containing silver nanoparticles.

/ 2

(b)

The socks are washed many times during their lifetime.

Suggest one possible risk to the environment of using silver nanoparticles in socks.

/ 2

Question 0

3 marks

Glass-reinforced plastic (GRP) is used to make the hulls of small boats. The table gives some data about GRP and about the two materials it is made from.

Material	density in g/cm³	tensile strength in MPa	flexibility
glass fibre	2.6	2000	very low (brittle)
polyester resin	1.2	50	high
GRP	1.7	400	medium

(a)

State what is meant by the term composite.

/ 1

(b)

Explain, using data from the table, why GRP rather than polyester resin alone is used for boat hulls.

/ 2

Question 0

6 marks

An engineer is choosing a material for the outer panels of an aircraft wing. The table gives data about four materials.

Material	density in g/cm³	tensile strength in MPa	maximum operating temperature in °C	relative cost
poly(propene)	0.90	35	100	1
aluminium alloy	2.7	480	200	2
steel	7.9	700	500	1
carbon fibre composite	1.6	1200	180	8

The panels must be as light as possible, must not break under the large forces acting on the wing, and must not be damaged at the surface temperatures reached in flight, which can be up to 120 °C.

(a)

The strength-to-density ratio of a material is calculated using

$\text{strength-to-density ratio} = \frac{\text{tensile strength in MPa}}{\text{density in g/cm}^3}$

Calculate the strength-to-density ratio of the aluminium alloy and of the carbon fibre composite.

/ 2

(b)

Use the data in the table, and your answers to part (a), to justify which material the engineer should choose for the wing panels.

/ 4

Atomic Structure

States of Matter & Mixtures

Chemical changes

Extracting metals & equilibria

Separate Chemistry 1

Groups in the periodic table

Rates of reaction & energy changes

Fuels & Earth science

Separate Chemistry 2

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Question 2

Question 3

Question 0

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