chem

Question 1

what are the 3 subatomic particles?

Answer 1

protons, neutrons and electrons

Question 2

what is the charge of a proton?

Answer 2

positive

Question 3

what is the charge of a neutron?

Answer 3

none

Question 4

what is the charge of an electron?

Answer 4

negative

Question 5

what is the number on top of the element on the periodic table?

Answer 5

mass number (no. of protons + no. of neutrons)

Question 6

what is the number below the element on the periodic table?

Answer 6

atomic number (no. of protons and no. of electrons)

Question 7

how many electrons can be in each shell?

Answer 7

1st- max 2
2nd and 3rd- max 8

Question 8

why do atoms have no overall charge?

Answer 8

because the number of protons is equal to the number of electrons, so the charges cancel each other out

Question 9

what is ionic bonding?

Answer 9

when atoms bond and they a gain or lose electrons

Question 10

what is covalent bonding?

Answer 10

when metals and non metals bond and they share a PAIR of electrons

Question 11

what is metallic bonding?

Answer 11

when metals bond

Question 12

describe the structure of a metal

Answer 12

-giant lattice/regular layers
-positive metal ions
-sea of delocalised electrons
-carries charge/thermal energy

Question 13

why are alloys stronger than pure metals?

Answer 13

the different sized atoms distort layers, meaning its harder for them to slide over each other

Question 14

what metals are extracted by electrolysis?

Answer 14

K, Na, Li, Ca, Mg and Al (first 6 in the reactivity series)

Question 15

what metals are extracted by reduction?

Answer 15

everything below carbon because carbon is used in reduction

Question 16

which metals are native and unreactive?

Answer 16

Ag, Au and Pt

Question 17

what is displacement?

Answer 17

when more reactive metals displace less reactive metals

Question 18

what are alkanes?

Answer 18

saturated hydrocarbons

Question 19

how do alkanes react to bromine water?

Answer 19

they stay orange

Question 20

what is the general formula for alkanes?

Answer 20

CnH2n+2

Question 21

what are alkenes?

Answer 21

unsaturated hydrocarbons

Question 22

how do alkenes react to bromine water?

Answer 22

they turn colourless

Question 23

what is the general formula for alkenes?

Answer 23

CnH2n

Question 24

explain fractional distillation

Answer 24

-crude oil heated until vaporised
-temperature decreases bottom to top
-fractions condense at different heights
-depending on their boiling point

Question 25

what is cracking?

Answer 25

turns longer chained hydrocarbons into smaller chained hydrocarbons eg fuels

Question 26

what are the two conditions needed for cracking?

Answer 26

high temperature and a catalyst

Question 27

what type of melting and boiling points do pure substances have?

Answer 27

fixed

Question 28

what type of melting and boiling points do impure substances have?

Answer 28

a range

Question 29

what does distillation do?

Answer 29

separates a mixture of liquids with different boiling points

Question 30

what does evaporation do?

Answer 30

separates a soluble solid from a solvent

Question 31

what does filtration do?

Answer 31

separates an insoluble solid from a solution/solvent

Question 32

what is the test and result for hydrogen gas?

Answer 32

lit splint, squeaky pop

Question 33

what is the test and result for oxygen gas?

Answer 33

glowing splint, lights again

Question 34

what is the test and result for carbon dioxide gas?

Answer 34

limewater, turns limewater cloudy

Question 35

what is the test and result for chlorine gas?

Answer 35

damp blue litmus paper, litmus bleaches white

Question 36

what is the line at the top of the chromatography paper called?

Answer 36

solvent front

Question 37

what is the liquid called?

Answer 37

solvent

Question 38

what is the paper and solvent placed in?

Answer 38

beaker

Question 39

why is the baseline drawn drawn in pencil rather than pen?

Answer 39

because a pen would dissolve in the solvent

Question 40

what happens to the rf value when the substance is more soluble?

Answer 40

its more soluble and so travels higher up the paper

Question 41

what happens to the rf value when the substance is less soluble?

Answer 41

it has a lower rf value and so doesn’t travel as far up the paper

Question 42

how do you work out the rf value?

Answer 42

distance moved by substance/distance moved by solvent

Question 43

what does it mean if the rf is over 1?

Answer 43

its wrong

Question 44

what is the relative mass of a proton?

Answer 44

1

Question 45

what is the relative mass of a neutron?

Answer 45

1

Question 46

what is the relative mass of an electron?

Answer 46

0

Question 47

what are the characteristics of a solid?

Answer 47

-tightly packed, high density -cannot be compressed -fixed position, vibrate on spot -forces between

Question 48

what are the characteristics of a liquid?

Answer 48

-close together -cannot be compressed -can move around -forces between particles are weaker, can be poured

Question 49

what are the characteristics of a gas?

Answer 49

-spread apart -can be compressed -can move in all directions -extremely weak forces, can flow/be poured

Question 50

what is the process when a liquid turns to gas?

Answer 50

evaporation

Question 51

what is the process when a liquid turns to solid?

Answer 51

freezing

Question 52

what is the process when a gas turns to liquid?

Answer 52

condensation

Question 53

what is the process when a gas turns to solid?

Answer 53

deposition

Question 54

what is the process when a solid turns to liquid?

Answer 54

melting

Question 55

what is the process when a solid turns to gas?

Answer 55

sublimation

Question 56

why does metal conduct electricity?

Answer 56

-there are delocalised electrons -which carry charge through the structure

Question 57

what can you use to remember the reactivity series?

Answer 57

please stop calling me a (careless) zebra, instead try learning (how) copper saves gold

Question 58

what is a metal ore?

Answer 58

a rock that contains enough of a metal or metal compund to make it worth extracting the metal

Question 59

how can you tell if a metal is worth extracting?

Answer 59

-how easy it is to extract from its ore -how much metal the ore contains -the demand for a particular metal

Question 60

what is a homologous series?

Answer 60

a group of chemicals (eg alkanes) which have similar chemical properties and can be represented as a general formula (eg CnH2n+2)

Question 61

the longer the hydrocarbon chain…

Answer 61

-the more viscous it is -the higher the boiling point -the harder it is to vaporise -the less flammable it is

Question 62

what is the equation for complete combustion?

Answer 62

hydrocarbon + oxygen -> carbon dioxide + water

Question 63

what is the equation for incomplete combustion?

Answer 63

hydrocarbon + oxygen -> carbon monoxide + carbon + water

Question 64

why is carbon monoxide dangerous?

Answer 64

because its absorbed in the lungs and binds within the haemoglobin in our red blood cells. this reduces the capacity of the blood to carry oxygen

Question 65

what is a formulation?

Answer 65

a mixture that has been designed as a useful product. in a formulation, the quantity of each component is carefully measured so that the product has the properties we need

Question 66

what is a mixture?

Answer 66

made up of two or more substance that are not chemically joined together

Question 67

what does a pure substance look like in chromatography?

Answer 67

it will only have one spot

Question 68

what does a mixture look like in chromatography?

Answer 68

it will have more than one spot on top of each other

Question 69

how do you make hydrogen?

Answer 69

a metal and an acid

Question 70

how do you make oxygen?

Answer 70

hydrogen peroxide and a catalyst

Question 71

how do you make carbon dioxide?

Answer 71

marble chips and hydrochloric acid