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Flashcards in C1c Deck (23):
1

What is a solution?

-mixture of solute and solvent that does not separate

2

What is a solvent?

-liquid a solute is dissolved into

3

What is a solute?

-a substance being dissolved

4

What does insoluble mean?

-will not dissolve

5

What does soluble mean?

-will disolve

6

What does solubility mean?

-measure of how much will dissolve

7

Why is nail vanish insoluble in water?

-the attraction between nail polish molecules to each other is stronger than its attraction to water molecules
-the attraction between water molecules to each other is stronger than its attraction to nail polish molecules
-more attracted to themselves than each other, and don't form a solution

8

Why is nail vanish soluble in acetone?

-the attractions between acetone molecules(nail polish remover) and nail polish molecules is stronger than the attractions holding the substances together

9

What do paints contain?

-pigment to give colour
-binding medium: carries pigment bits and holds them together, when it goes solid it stick the pigment to the painted on surface
-solvent: thins the paint and makes it easier to spread

10

What are colloids?

-tiny particles of one substance dispersed into another substance
-mixed but not dissolved

11

Why do colloids not separate?

-the particles are too small
-they don't settle out at the bottom

12

How do water-based (emulsion) paints dry?

-solvent used is water
-binding medium usually an acrylic or vinyl acetate polymer
-solvent evaporates, leaving the binder and pigment
-a thin layer dries quite quickly
- ideal for inside walls

13

How do oil-based paints dry?

-solvent:organic compound that dissolves oil
-binding medium is oil
1-solvent evaporates
2-the oil is oxidised by the air before it turns solid
-ideal for outside doors and metalwork

14

What are the advantages and disadvantages of oil paints?

-advantages:glossy, waterproof, hard-wearing
-disadvantages: solvents used often produce harmful fumes

15

What are the advantages of water-based paints?

-fast-drying, no harmful fumes

16

What are thermochromic pigments?

-pigments that change colour or become transparent when heated or cooled
-different pigments change colour at different temperatures
-a mixture of pigments can be used to make a colour-coded temperature scale, which are used to make basic thermometers that stick to your head and take temperature

17

What are some uses for thermochromic pigments?

-electric kettles that change colour as water boils
-baby products, e.g. bath toys and baby spoons, often have them added as a safety feature
-drink mugs to tell if drink it too hot
-mood rings

18

What happens if you mix thermochromic pigments with paint?

-mix with acrylic paint to give a wide range of colour changes
-e.g. blue thermochromic pigment loses colour at 27C, , with a yellow acrylic paint would give a paint that's green below 27C and yellow above 27C
-the blue pigment has become transparent

19

How do phosphorescent pigments work?

-absorb natural or artificial light and store energy in their molecules.
-energy is released as light over a period of time

20

What did people use to paint glow-in-the-dark watches and what was wrong with it?

-radioactive paints
-they would glow for years without being needed 'charging' by putting them in light
-they were not safe and could give quite a dose of atomic radiation

21

What are some uses of thermochromic pigments mixed with paint?

-these are also used in novelty mugs, designed to change colour when a hot drink is poured inside or become transparent and reveal a picture

22

What does solubility depend on?

-the solvent used

23

What are some uses of phosphorescent pigment?

-watches and clocks with glow-in-the-dark hands
-traffic lights
-toys
-novelty decorations
-emergency exit signs