Chemistry

Question 1

Which changes of state need energy?

Answer 1

Melting, evaporating and sublimation

Question 2

What is an atom?

Answer 2

Simplest thing that can exist on its own

Question 3

What is a molecule?

Answer 3

2 or more atoms joined together by covalent bonds

Question 4

What is an ion?

Answer 4

Charged particle

Question 5

What is a mixture?

Answer 5

2 or more substances not chemically joined together

Question 6

Describe the structure of the atom

Answer 6

Nucleus that contains protons and neutrons with electrons in shells orbiting it

Question 7

What is the mass of a proton? neutron? electron?

Answer 7

P= 1, n = 1, e 1/1840 or negigible

Question 8

What are the charges on a proton? neutron? electron?

Answer 8

p = +, n = 0, e = -

Question 9

What does the proton number (atomic number) tell you?

Answer 9

Number of protons (which equals the number of electrons in an atom)

Question 10

How do you work out the amount of neutrons?

Answer 10

Mass number - atomic number

Question 11

How is a positive ion formed? What does this happen in?

Answer 11

Lose an electron - metals

Question 12

How is a negative ion formed?

Answer 12

Gain an electron - non metals

Question 13

What happens in an ionic bond?

Answer 13

Electrons are given from metals to non-metals

Question 14

What happens in a covalent bond?

Answer 14

Electrons are shared between non-metals

Question 15

Which is the stronger bond covalent or ionic?

Answer 15

Ionic

Question 16

What are the differences between ionic and covalent compounds?

Answer 16

Ionic have higher mpt and bpt, are soluble in water, conduct electricity when molten, not volatile (do not evaporate easily)

Question 17

What does exothermic mean?

Answer 17

Gives out heat or energy

Question 18

What does endothermic mean?

Answer 18

Takes in heat

Question 19

In a chemical reaction what happens?

Answer 19

Bonds broken (endothermic) then new bonds made (exothermic)

Question 20

What is loss of oxygen in a reaction called?

Answer 20

Reduction

Question 21

What is gain of oxygen in a reaction called?

Answer 21

Oxidation

Question 22

In the reaction
Ca0 + Mg = MgO + Ca
What was oxidised and what was reduced?

Answer 22

Ca = reduced
Mg = oxidised

Question 23

What does the group number on the periodic table tell you?

Answer 23

Number of outer electrons

Question 24

What are group 1 called?

Answer 24

Alkali metals

Question 25

What happens as you go down group 1?

Answer 25

More reactive, less dense, lower mpt, less dense

Question 26

What are group 7 called?

Answer 26

Halogens

Question 27

What happens as you go down group 7?

Answer 27

Less reactive, more dense (more solid), darker colour

Question 28

Will a reaction occur? | Sodium chloride + iodine

Answer 28

No as Iodine is less reactive than chlorine

Question 29

Will a reaction occur? | Sodium chloride + fluorine

Answer 29

Yes as fluorine is more reactive than chlorine

Question 30

What are the properties of transition metals

Answer 30

High density, high mpt, conductors, coloured compounds, used as catalysts

Question 31

What is group 8 or 0 called?

Answer 31

Noble gases

Question 32

What are noble gases used for?

Answer 32

Lighting and balloons

Question 33

Why are the noble gases monoatomic?

Answer 33

Do not react as have a full outer shell

Question 34

What are ph1-6?

Answer 34

Acid

Question 35

What is pH 7?

Answer 35

Neutral

Question 36

What is ph 8-14?

Answer 36

Alkali

Question 37

Name the 3 acids, their formula and the salts they make

Answer 37

Hydrochloric HCl - chlorides Sulphuric H2So4 - sulphates Nitric HNO3 - Nitrates

Question 38

How do you make an insolube salt?

Answer 38

Mix and wait till you see no more reaction then filter and the salt is in the filter paper

Question 39

How do you make a soluble salt?

Answer 39

Mis and wait till you see no more reaction, filter then evaporate to leave the salt crystals

Question 40

What does metal + acid make?

Answer 40

Salt + hydrogen

Question 41

What does metal oxide + acid make?

Answer 41

Salt + water

Question 42

What does metal hydroxide + acid make

Answer 42

salt + water

Question 43

What does metal carbonate + acid make?

Answer 43

salt + water + carbon dioxide

Question 44

What are the properties of metals?

Answer 44

conductors of heat and electricity, high mpt. high bpt, malleable, ductile

Question 45

What is an alloy? Draw a diagram

Answer 45

Mixture of metals

Question 46

Why use an alloy of iron (steel) rather than iron?

Answer 46

stronger, doesn't rust

Question 47

What are the metals in order of reactivity

Answer 47

``` Potassium Sodium Calcium Magnesium Aluminium Zinc Iron Copper ```

Question 48

What makes one metal more reactive than another

Answer 48

The less electrons it has to lose and how easy it is to lose them to form a positive ion

Question 49

What colour does water turn copper sulfate?

Answer 49

Turns from white to blue

Question 50

What colour does water turn cobalt chloride?

Answer 50

Turns blue to pink

Question 51

What is air made up of?

Answer 51

78% Nitrogen, 21% oxygen then small quantities of CO2 etc

Question 52

What are 3 common pollutants in air?

Answer 52

Carbon monoxide, sulphur dioxide and oxides of nitrogen

Question 53

Which gas causes acid rain

Answer 53

Sulphur dioxide

Question 54

What are some effects of acid rain?

Answer 54

Kill trees, fish and damage bulidings

Question 55

Name 2 greenhouse gases

Answer 55

CO2 and methane (cows farts)

Question 56

What do greenhouse gases do?

Answer 56

Cause global warming

Question 57

What is needed for rust?

Answer 57

iron, water and oxygen

Question 58

What is the chemical name for rust?

Answer 58

iron oxide

Question 59

How can you prevent rust?

Answer 59

Paint, oil etc