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Flashcards in Module 1 Deck (60):
1

How do emulsion paints dry?

The solvent in the paint (water) evaporates

2

How do oil paints dry?

The solvent in the paint (hydrocarbon oil) evaporates and then oxygen oxidises the hydrocarbon molecules

3

What are thermochromic substances?

A substance that changes colour according to temperature (e.g. baby spoons and thermometers)

4

How do phosphorescent pigments work?

They absorb energy when they are in light, and then they can glow in the dark. They are used in road signs and clocks.

5

Why are phosphorescent pigments safer than radioactive pigments?

Because radioactive pigments can cause damage to cells and cause cancer.

6

What is a colloid?

A paint mixture when particles are mixed and dispersed in a liquid but are not dissolved

7

Why do the components of colloids not settle?

Because the particles are too small to settle

8

Name 3 examples of fossil fuels

Crude oil, coal and gas

9

What type of resource is a fossil fuel?

They are finite resources which means they are no longer being made or made extremely slowly. And they are non renewable which means they are used faster than they are formed

10

What is crude oil?

A mixture of hydrocarbons , a hydrocarbon contains ONLY hydrogen and carbon atoms

11

How does fractional distillation work?

The coolest part is at the top and the hottest part is at the bottom. It works because the different hydrocarbons have different boiling points. The low boiling points exit the top and the high boiling points exit at the bottom. The larger the hydrocarbon molecules the stronger the intermolecular force which is why they are at the bottom because they need a higher temperature to break the intermolecular forces.

12

What are the problems with oil?

Damage to wildlife/beaches and oil slicks

13

What are alkanes?

Hydrocarbons that contain single covalent bonds between carbon atoms

14

What are alkenes?

Hydrocarbons which contain a double covalent bond

15

Molecules with double bonds are said to be what?

Unsaturated

16

When is a double covalent bond formed?

When 2 atoms share 2 pairs of electrons

17

What is used for testing unsaturation?

Bromine water is orange and if it's unsaturated a colourless dibromo compound is formed

18

What is an atom?

The smallest part of an atom that can exist

19

How many elements are there approximately?

About 100

20

What are compounds and how are they formed?

Compounds are formed from elements by chemical reactions. Compounds contain two or more elements chemically combined.

21

How can compounds be separated?

Only by chemical reactions

22

What is a mixture?

A mixture consists of 2 or more elements that are not chemically combined, the chemical properties of a mixture are unchanged

23

How can mixtures be separated?

1) Filtration
2) Chromatography
3) Crystallisation
4) Fractional Distillation
5) Simple Distillation

(These do not involve chemical reactions)

24

What is the radius of an atom?

0.1nm

25

What is an atom?

A nucleus surrounded by electrons

26

Where are the protons and neutrons?

Nucleus

27

Mass and charge of a proton?

Mass - 1
Charge - +1

28

Mass and charge of neutron?

Mass - 1
Charge - 0

29

Mass and charge of an electron?

Mass - very small
Charge - -1

30

What is atomic number?

The number of protons in an atom

31

What is mass number?

The total number of protons and mass number in an atom

32

When are positive ions formed?

When an atom loses electrons

33

When are negative ions formed?

When an atom gains an electron

34

What are elements in Group 0 called?

Noble gases

35

Why are noble gases unreactive?

Because their atoms have stable arrangements of electrons

36

What happens when you go down the group?

The boiling point increases

37

How are the elements in the periodic table arranged?

In order of atomic number

38

Why is it called the periodic table?

Because similar properties occur at regular intervals

39

Why do elements in the same group have similar chemical properties?

Because they have the same number of electrons in their outer shell

40

What does periods tell you about the element?

The number of shells the electrons fill

41

How was the periodic table ordered before now?

In order of atomic weights

42

What did Mendeleev do?

He sorted some problems by leaving gaps for undiscovered elements and changed the order in some places. The gals were the filled and knowledge of isotopes made it possible to explain why the order of atomic weights wasn't always correct.

43

What was the problem with Döbereiner's ideas?

He could not explain his observations

44

Why was Newland's version of the periodic table dismissed?

He ordered them in order of relative atomic mass but it only worked for first 20 elements, up to Calcium

45

Why was Mendeleev's ideas accepted?

He swapped some elements around and left gaps for undiscovered elements

46

Which elements form positive ions?

Metals

47

Where are metals in the periodic table?

Left and towards the centre

48

Name the properties of metals

Ductile
Good conductor of electricity
Good conductor of heat
Lustrous
High melting point
High density
Strong
High density
Hard

49

Why is iron used in buildings?

Because it is strong and has a high melting point

50

Why is copper used in wires?

Because it is ductile and a good conductor of electricity

51

What elements from negative ions?

Non metals

52

Where are non metals found?

To the right and top of the periodic table

53

How many electrons do Group 1 have in their outer shell?

1 election

54

Why are Group 1 metals stored in oil?

Because they are so reactive

55

Why are they called alkali metals?

Because when they react they produce alkaline solutions

56

What are the Group 1 elements like?

They have a low density, the first 3 metals are less dense than water

57

How do Group 1 metals react with water?

They are white solids that dissolve in water to form colourless solutions
Hydrogen is formed
They all react vigorously with water
Metal hydroxide is formed that dissolves in water to give alkaline solutions
Reactivity increases down the group

58

What type of elements are the Group 7 elements?

Non metals, that consist of molecules which are made up of pairs of atoms. They react with metals to form ionic compounds which the halide iron carries a charge of -1

59

Trends in Group 7

Decreases in reactivity down the group
Boiling and melting point increases

A more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt

60

Properties of transition metals

Compared with group 1:
Higher melting points (except mercury) and higher densities
Stronger and harder
Less reactive don't react with water or oxygen