CHEMISTRY PART 1 and 2 Flashcards

Question

What happens in the ionic bonding of sodium chloride?

Answer 1

The single electron on Sodium's outer shell transfers to become the 8th electron of Chlorine's outer shell. Sodium becomes positively charged, Chlorine becomes negatively charged. Na+ Cl- Final product - NaCl

Answer 2

The two electrons from Magnesium outer shell transfer to Oxygen's outer shell that would've had 6 electrons. Magnesium becomes positively charged, oxygen becomes negatively charged. Mg2+ 02- Final product - MgO

Answer 3

``` Calcium has two elections on its outer shell. Each goes to a chlorine atom which gain a single electron to complete the full outer shell. The chlorine's become negatively charged, and the calcium becomes positively charged. Ca2+ Cl- Cl- Final product - CaCl2 ```

Answer 4

The sharing of electrons within a compound to achieve a full outer shell

Answer 5

2 non metals

Answer 6

The covalent bonds are strong but the intermolecular forces between the molecules are weak

Answer 7

Boiling or melting the substances

Answer 8

They have no overall charge | There are no charge carriers (free electrons/free ions)

Answer 9

Hydrogen Oxygen Methane Chlorine

Answer 10

Size and the shape of a molecule

Answer 11

As the molecules cannot get as near to one another

Answer 12

Hydrogen have one electron and only require one more for a full outer shell. Therefore they overlap to share two electrons between both.

Answer 13

Chlorine atoms have 7 electrons on their outer shell. | Therefore for the bonding of two chlorine atoms, they share their seventh electron where they overlap.

Answer 14

Carbon has four electrons on its outer shell. Therefore it forms four covalent bonds with four hydrogen atoms. Within the overlap there is one electron from hydrogen and one from chlorine (2 in total) So chlorine has 8 electrons in total and all the hydrogens have a full outer shell too.

Answer 15

Hydrogen and chlorine both require only one more electron for a full outer shell. Therefore, they share two electrons within the one overlap.

Answer 16

Nitrogen has 5 electrons on its outer shell. The final 3 of the 5 each form a covalent bond with a hydrogen atom. Therefore, they all have a full outer shell.

Answer 17

Oxygen has 6 electrons on its outer shell. It bonds with 2 hydrogen atoms. Therefore there are two electrons in the overlap.

Answer 18

Both oxygen atoms have 6 electrons on its outer shell. Two electrons from each are shared in the overlap (4 in total) to create a full outer shell. Therefore, a double covalent bond is formed.

Answer 19

Gases and liquids... although they CAN be solids

Answer 20

Giant covalent structures or lagged covalent bonded molecules

Answer 21

No charged ions Do not conduct electricity even when molten (except graphite) High MP and BP Bonded by strong covalent bonds

Answer 22

Diamond Graphite Silicon dioxide (silica)

Answer 23

``` Made up carbon Each carbon atoms forms four covalent bonds with other carbon atoms Rigid structure Hardest natural substance Used for drill tips ```

Answer 24

Each carbon atoms forms 3 covalent bonds - creating layers The bonds are strong but intermolecular forces between the layers are weak Layers slide which is how a pencil works Soft and slippery Only non metal that conducts heat electricity as each carbon atom has one free/delocalised electron

Answer 25

``` Conduct heat Conduct electricity Sonorous Ductile High MP and BP Hard Malleable ```

Answer 26

Makes a ringing sound when hit

Answer 27

Can be hammered/ bent into different shapes

Answer 28

Can be drawn into wires

Answer 29

Free electrons

Answer 30

The outer shell of every atom in the giant structure

Answer 31

They hold the atoms together as the strong electrostatic forces attract the positive metal ions and negative metal ions

Answer 32

The free electrons are negatively charged and therefore attract the positive ions by electrostatic forces. The strong forces are difficult to overcome, hence the high BP and MP

Answer 33

The free ions are free to move and carry the charge

Answer 34

The position of ions can change because of the movement of free electrons The layers of atoms can slide over each other allowing it to be bent/shaped

Answer 35

A mixture of 2 or more metals, usually to create a material with more desirable properties

Answer 36

Different sized elements have different sized atoms Therefore a mixture of the two, distorts the the regular arrangement This makes it difficult for the atoms to slide over each other Therefor they are harder than pure metals

Answer 37

Amalgam, mostly mercury, used in dental fillings Brass, mostly copper and zinc, used in hinges/electrical plugs Solder, mostly lead and tin, used to join metals

Answer 38

Behave different/have unusual properties depending on conditions e.g. Temperature

Answer 39

Nitinol (nickel and titanium) Metal alloy If bent out of shape, it returns when heated or an electric current is passed through it Useful for glasses frames and some dental braces

Answer 40

Buckminister fullerene | Nanotube

Answer 41

Hexagon shape, connected to make a sphere | Uses included drug delivery in body, lubricants and catalysts

Answer 42

Light Potentially strong Tube structure of carbon in hexagons Uses include reinforcing materials e.g tennis racket

Answer 43

``` VERY small 1-100nm across Include fullerenes Contain a few hundred atoms Different properties Very large surface area to volume ratio ```

Answer 44

They have a large surface area to volume ratio (for the amount of material, the surface area is huge)

Answer 45

``` New industrial catalysts Highly specific sensors Stronger, lighter building materials Sun tan/deodorant Nanomedicine e.g. Drug delivery Lubricant coatings Electric circuits for computer chips ```

Answer 46

The forces between the molecules

Answer 47

The strong covalent bonds

Answer 48

They are held together by weak intermolecular forces and therefore become more tangled They are free to slide over each other

Answer 49

They have stronger intermolecular forces called crosslinks | This holds the chains firmly together

Answer 50

Low density poly(ethene)

Answer 51

High density poly(ethene)

Answer 52

They are made under different conditions

Answer 53

Polymers have side branches that disrupt the regular arrangement so it has a LOW density Forces of attraction are weak as chains are further apart More transparent and flexible then HDPE

Answer 54

``` Molecules line up so the density is HIGH Molecules are held together strongly so it has a high melting point Forces of attraction are strong Very few, if any side branches Stiff, rigid and strong ```

Answer 55

Bags and bottles

Answer 56

Water tanks and drain pipes

Answer 57

Hearing ethene to 100-300 degrees under high pressure | Oxygen used in reaction

Answer 58

Made at a lower temperature and pressure with a aluminium based metal oxide as a catalyst

Answer 59

No regular structure Forces between chains are easy to overcome Easy to melt Can be remelted and remoulded as many times as you like

Answer 60

``` They have cross links which hold it together in a solid structure Strong covalent bonds Doesn't soften when heated Difficult to melt Cannot be remoulded once heated Strong, hard and rigid ```

Answer 61

Plastic bottles | Containers

Answer 62

Cooking spatulas Pan handles Plug sockets

Answer 63

Weak intermolecular forces | Polymers can separate more easily at lower temperatures so les heat is needed to separate the chains

Answer 64

How heavy different atoms are compared with the mass of an atom of carbon 12

Answer 65

It's the same as the mass number of the element (top number)

Answer 66

Relative atomic masses added together OR The relative formula mass of a substance, in grams is one mole of that substance.

Answer 67

Number of moles = Mass in g of the element/ compound DIVIDED BY The relative formula mass of the element/ compound

Answer 68

``` Percentage mass = Relative formula mass of element x number of atoms of the element DIVIDED BY Relative formula mass of compound MULTIPLIED BY 100 ```

Answer 69

23 x 2 divided by 106 times 100 equals | 43.4%

Answer 70

1. List all elements given 2. Below, write the masses or percentages given 3. Divide each mass or percentage by the relative formula mass (masses added together) 4. Divide both answers by the smallest answer 5. Write out the empirical formula

Answer 71

1. C= 1.2g, O=3.2g 2. C=12, O=16 3. C= 1.2/12=0.1, O=3.2/16=0.2 4. C= 1.2/1.2=1, O=0.2/0.1=2 5. CO2

Answer 72

1. Write out the balanced equation 2. Work out the relative formula mass (for the two bits you need) 3. Divide to get one, then multiply to get all (do this on both sides)

Answer 73

``` Percentage yield = actual yield (grams) DIVIDED BY predicted yield (grams) TIMES BY 100 ```

Answer 74

Tells you the overall success of an experiment | It compares the predicted yield and the actual yield

Answer 75

The amount of product you get from a reaction

Answer 76

The amount of reactants you started with, because it is a percentage

Answer 77

Using the balanced equation reaction

Answer 78

Theoretical yield

Answer 79

You got all the product you expected to get

Answer 80

No reactants were converted into a product, so no product was made

Answer 81

Some product or reactant will always get lost along the way (including big industrial processes as well as school lab experiments)

Answer 82

1. Reversible reactions 2. Filtration 3. Unexpected reactions

Answer 83

Reactants will never be completely converted to products as the reactions goes both ways, which results in a lower yield

Answer 84

When you filter a liquid to remove solid parts, you always lose a bit as it may get separated from the reaction mixture

Answer 85

Unexpected reactions may use up reactants, so there is not as much reactants to make the product you want

Answer 86

Where the products of the reaction can react with themselves to product the original reactants

Answer 87

Ammonium chloride ammonia + hydrogen chloride

Answer 88

Making sure we don't use resources faster than we can replace them

Answer 89

It uses little energy | Resources are saved

Answer 90

Chemicals are wasted

Answer 91

It will move furthest up the paper

Answer 92

Separating artificial colours such as food colouring (containing one dye or a mixture of dyes)

Answer 93

- Extract the sample into a cup with water - Draw a pencil baseline on some filter paper and add spots of the coloured solution - Add the paper into the water, making sure the pencil like is above the solution - Different dyes will then form onto the paper

Answer 94

At least four dyes, not exactly four dyes

Answer 95

Separating a mixture of compounds and helping to identify the substances present

Answer 96

- A carried gas carries substances through a column with solid material - the substances travel and different speeds so they are separated - the detector helps to identify the substances - a recorder then draws a gas chromatograph

Answer 97

The time it takes for the substances to reach the detector

Answer 98

The number of different compounds in the sample

Answer 99

The retention time of each substance

Answer 100

When the gas chromatography column is linked to a mass spectrometer. It identifies the substances leaving the column QUICKY and ACCURATELY

Answer 101

Read it from the molecular ion peak on the graph it draws | the peak furthest to the right

Answer 102

- sensitive - fast - accurate

Answer 103

``` Paper - Mobile phase is liquid Analyse food dyes Stationary phase is paper Easy to do Difficult to obtain accurate results Substances travel at different speeds Analyse mixtures in a solution ```

Answer 104

``` Gas - Mobile phase is gas Used to detect alcohol in breath Stationary phase is a solid packed in a column Requires special equipment Gives accurate results Substances travel at different speeds Analyse substances in a vapour Sensitive ```

Answer 105

The rusting of iron

Answer 106

Metal reacting with an acid

Answer 107

An explosion

Answer 108

- Temperature - Concentration (or pressure for gases) - Catalyst - Surface area of solid

Answer 109

How quickly the reacts are used up | How quickly the products are formed

Answer 110

Rate of reaction= Amount of reactant used/product formed DIVIDED BY time

Answer 111

Precipitation Change in mass (usually a gas given off) Volume of gas given off

Answer 112

This is when the product is a precipitate and makes the solution go cloudy You can observe a mark in the solution to see how long it takes for it to disappear The quicker it disappears, the quicker the reaction People may disagree to when the "mark" disappears

Answer 113

This can be carried out on a mass balance As the gas is released, the mass disappearing is measured on the balance The quicker the reading drops, the faster the reaction Most accurate However, the gas gets released straight into the room and if the flask is too hot, mass may be lost by evaporation

Answer 114

This involves a gas syringe The more gas given off in a certain time interval, the faster the reaction Mostly accurate results If the reaction is too vigorous, the plunger may blow out of the syringe

Answer 115

The theory that the rate of reaction depends on how often and how hard particles collide with each other

Answer 116

As temperature increases gain more kinetic energy Therefore they move faster Causing more successful collisions

Answer 117

A higher concentration/pressure means more particles are squashed together Therefore they are more likely to collide as there is less free space So there are more frequent collisions

Answer 118

A larger surface area means there is more area for the particles to react with So there is more frequent collisions

Answer 119

A catalyst provides a surface for reacting particles to stick to Which increases the number of successful collisions

Answer 120

A substance that speeds up a reaction without being changed or used up

Answer 121

The minimum amount of energy required for particles to react

Answer 122

Used in many industrial reactions Saves money Allows reactions to work at lower temperatures saving energy Can be reused

Answer 123

Expensive to buy and clean Different catalysts are required for different reactions Can stop working by impurities

Answer 124

When (heat) energy is transferred to the surrounding and is shown by a rise in temperature

Answer 125

- burning fuels e.g combustion - neutralisation reactions - oxidation reactions - everyday uses e.g hand warmers

Answer 126

Takes in (heat) energy from surroundings and is shown by a fall in temperature

Answer 127

- thermal decomposition | - everyday uses e.g injury ice packs

Answer 128

Without water

Answer 129

With water

Answer 130

The energy absorbed by the endothermic reaction is equal to the energy released

Answer 131

A measure of how acidic or alkaline a solution is

Answer 132

It is neutral, e.g pure water

Answer 133

Using an indicator

Answer 134

It changes colour depending on whether it is above or below a particular pH

Answer 135

Dissolved in water

Answer 136

An acid is a substance with a pH of less than 7

Answer 137

They form H+ ions which make solutions acidic

Answer 138

An alkali is a base that dissolves in water

Answer 139

A substance with a pH of above 7

Answer 140

They form OH- ions that make solutions alkali

Answer 141

A neutralisation reaction

Answer 142

acid + base -> salt + water

Answer 143

H+ (aq) + OH- (aq) -> H20 (l)

Answer 144

Acid + metal -> salt + hydrogen

Answer 145

The more reactive the metal, the faster the reaction will be

Answer 146

It is less reactive than hydrogen

Answer 147

The rate at which bubbles of hydrogen are given off

Answer 148

The test for hydrogen which can be identified by placing a burning splint into the solution and hearing a squeaky pop

Answer 149

The metal and acid used

Answer 150

Chloride | E.g. magnesium chloride

Answer 151

Sulfates | E.g Zinc sulfate

Answer 152

Acid + metal oxide -> salt + water (neutralisation reaction)

Answer 153

Acid + metal hydroxide -> salt and water (neutralisation reaction)

Answer 154

An Alkaline solution

Answer 155

Ammonia + nitric acid -> ammonium nitrate NH3 (aq) + HNO3 (aq) -> NH4NO3 (aq)

Answer 156

There is NO water produced, only three ammonium salt

Answer 157

It has nitrogen from the ammonia and the nitric acid which plants require to make proteins

Answer 158

Most chlorides, sulfates and nitrates | Except lead chloride, lead sulfate and silver chloride

Answer 159

Most oxides and hydroxides

Answer 160

1. Pick the correct acid and base/insoluble salt 2. Add the metal, metal oxide or hydroxide to the acid which should then dissolve as it reacts. 3. The acid has been neutralised when excess solid sinks to the bottom 4. Filter out the excess solid parts to leave the salt solution 5. For pure crystals, evaporate some of the water to make it more concentrated and leave to evaporate (crystallisation)

Answer 161

Acid + alkali -> salt + water 1. Use universal indicator to mix and see when the reaction is finished and measure the amount you have used 2. Repeat without the indicator so the salt is not contaminated with indicator 3. Evaporate and crystallise

Answer 162

Pick two solutions that contain the ions you need Mix them together Once the salt is precipitated, it will sink to the bottom Filter the solution, wash and then dry it on filter paper

Answer 163

- To remove poisonous ions e.g lead from drinking water | - To treat effluent (sewage) and removed unwanted ions

Answer 164

Passing an electric current through an ionic substance (that's molten or in solution) to break it down into the elements it's made up of

Answer 165

The liquid required to conduct the electricity

Answer 166

As electrolytes contain free ions that allow electricity to be conducted

Answer 167

Electrons are taken away from ions at the positive electrode and move the to the negative electrode

Answer 168

Atoms or molecules

Answer 169

Oxidation is losing electrons (and gaining oxygen) Reduction is gaining electrons (and losing oxygen)

Answer 170

- Lead is produces at the negative electrode (Reduction) - Bromine is produced at the positive electrode (Oxidation) - At the negative electrode, one lead ion accepts 2 electrons and becomes one lead atom - At the positive electrode, two bromide ions lose one electron each to become one bromine molecule

Answer 171

The reactivity series of metals

Answer 172

Hydrogen js produced unless the metal is less reactive than hydrogen This is because more reactive ions want to stay within the solution

Answer 173

If OH- and halide ions (Cl-, Br, l-) are present then one of the halide ions will form. If no halide is present, oxygen will be formed

Answer 174

Hydrogen Chlorine Sodium hydroxide

Answer 175

- At the negative electrode, two hydrogen ions accept 2 electrons to become one hydrogen molecule - At the positive ions, two chloride ions lose their electrons to become one chlorine molecule - Sodium ions remain in solution as they are more reactive than hydrogen, and hydroxide ions from the water are left behind. Therefore sodium hydroxide is left in the solution.

Answer 176

Negative electrode: Pb2+ + 2e- ---> Pb Positive electrode: 2Br- ---> Br2 + 2e-

Answer 177

Negative electrode: 2H+ + 2e- ---> H2 Positive electrode: 2Cl- ---> Cl2 + 2e- OR 2Cl- - 2e- ---> Cl2

Answer 178

- Chlorine can be used in the production of bleach and plastics - Sodium hydroxide is a strong alkali and is therefore used to make soap

Answer 179

It is used to remove aluminium (found naturally in compounds) from its ore which is bauxite After mining and purifying, pure aluminium oxide is left (a white powder), so the aluminium gets extracted through electrolysis

Answer 180

Aluminium oxide has a high MP (over 2000 degrees) so melting would be expensive Instead dissolving it in molten cryolite would bring the temperate down to 900 degrees This makes it cheaper and easier

Answer 181

It is a good conductor of electricity

Answer 182

Aluminium forms at the negative electrode Oxygen forms at the positive electrode At the positive electrode, carbon dioxide can get formed because the oxygen reacts with the carbon, therefore the positive electrodes have to get replaced as they can get eroded

Answer 183

Negative electrode: Al3+ + 3e- ---> Al Positive electrode: 202- ---> O2 + 4e-

Answer 184

Electroplating used electrolysis to coat the surface of one metal with another

Answer 185

Decoration - silver is attractive but expensive so it's character to plate a brass cup with silver instead Conduction - metals like copper conduct electricity well so they're used to plays metals for circuits and computers

Answer 186

The negative electrode is the metal object you want to plate The positive electrode is the pure metal you want it to be plated with The electrolyte must contain a solution containing the ions of the plating metal

Answer 187

Brass would be the negative electrode A lump of pure silver would be the positive electrode The electrolyte would be silver nitrate (as it includes silver ions)

Answer 188

HCL acid and marble chips Magnesium and dilute HCL Sodium Thiosulfate and HCL Hydrogen peroxide

Answer 189

Both clear solutions React to form a yellow precipitate (sulfur) Time how long it takes for a black mark to no longer be seen as the sulfur turns cloudy Repeat for different temps/concentrations Use hot water bath so acid is not directly heated

Answer 190

``` Shows the effect of different catalysts The decomposition is usually quite slow Manganese oxide catalyst speeds it up ( Or catalysts in potato peel/blood ) Oxygen is given off and if used to measure the rate of reaction using a gas syringe 2H202 (aq) ---> 2H20 (l) + O2 (g) ```

CHEMISTRY PART 1 and 2 Flashcards

(223 cards)