Paints and Pigments

Question 1

Relate the ingredients of a paint to their function:

Answer 1

• solvent thins the paint and makes it easier to
spread
• binding medium sticks the pigment in the paint to
the surface
• pigment is the substance that gives the paint its
colour.

Question 2

Oil paint properties

Answer 2

• have the pigment dispersed in an oil

* and often a solvent that dissolves oil.

Question 3

what are thermochromic pigments?

Answer 3

the change colour when heated or cooled

Question 4

what do phosphorescent pigments do?

Answer 4

they glow in the dark

Question 5

recall uses of thermochromic pigments

Answer 5

mugs
baby feeding spoons
bath toys

Question 6

describe paint

Answer 6

a colloid where the particles are
mixed and dispersed with particles of a liquid but are
not dissolved

Question 7

Describe how most paints dry:

Answer 7

• paints are applied as a thin layer

* the solvent evaporates

Question 8

describe emulsion paints

Answer 8

water based paints that dry when the solvent evaporates

Question 9

Explain why phosphorescent pigments glow in the

dark:

Answer 9

• they absorb and store energy

* then release it as light over a period of time.

Question 10

Explain how oil paints dry:

Answer 10

• the solvent evaporates

* the oil is oxidised by atmospheric oxygen

Question 11

Explain why thermochromic pigments are suited to a

given use

Answer 11

they are useful to make sure liquids are not too hot

Question 12

Explain why the components of a colloid will not

separate

Answer 12

solid pigment particles are spread out in a liquid but they are not dissolved

Question 13

Explain how acrylic paints can be added to
thermochromic pigments to make even more colour
changes

Answer 13

when the thermochromic pigments goes colourless, the acrylic paint colour is seen

Question 14

why are phosphorescent paints a safer alternative?

Answer 14

because early glow in the dark paints were radioactive - harmed workers who painted with them (e.g. cancer)