chemistry

Question 1

diameter of nucleus vs atom

Answer 1

1/20000

Question 2

electron to proton size

Answer 2

1/1837

Question 3

radius of nucleus/radius of atom

Answer 3

nucleus/27000

Question 4

cathodes

Answer 4

reduces cations
cations are postitve
cathodes are negatiove

Question 5

anodes

Answer 5

oxides anodes
anodes are postitve
anions are negatives

Question 6

Fractional Distillation

Answer 6

Crude Oil is a mixture of lots and lots of hydrocarbons. We use fractional distillation to separate them from one another.
The heavier a compound (ie: the more carbons it has), the higher its boiling point. That means that as you go up the fractional distillation column, and as the temperature decreases, the heavier compounds leave the column first (towards the bottom of the column where the temperature is highest), and the really light compounds leave the column towards the top where the temperature is lower.
The majority of hydrocarbons in crude oil are alkanes (which we’ll go over in the next topic), with just a few alkenes (in the topic after that).

Question 7

Properties Of Fractions

Answer 7

Boiling Point - We’ve already mentioned that the heavier compounds have higher boiling points.

Question 8

Volatility -

Answer 8

The volatility of a compound is its propensity to evaporate at a given temperature. The heavier compounds are less volatile.

Question 9

Flammability -

Answer 9

The smaller compounds are more flammable. This is because it’s easier for Oxygen molecules to react with smaller compounds than bigger ones.

Question 10

Viscosity -

Answer 10

The heavier compounds are more viscous. This makes intuitive sense - we can imagine bigger, heavier compounds being thicker in their liquid form than smaller ones.

Question 11

Burning Hydrocarbons

Answer 11

When you burn a hydrocarbon properly (complete combustion), you should get Carbon Dioxide and Water (and energy).
When you burn a hydrocarbon not-properly (incomplete combustion), you get a mixture of carbon, carbon dioxide, water and carbon monoxide. Carbon Monoxide (CO) is very bad for you and will kill you if you inhale too much of it [1]
Because combustion produces energy, hydrocarbons are often used as fuels. Of course, this produces lots of CO2 which is bad for the environment.

Question 12

alkene test

Answer 12

bromine test

Question 13

alkenes undergo

Answer 13

electrophillic reactions

Question 14

alkenes attract

Answer 14

electrophiles

Question 15

alkens are technolically

Answer 15

Alcohols have the -OH functional group, and the suffix -ol.
The first three (the ones shown above) have similar properties.
They’re flammable, and so they’re used as fuels that burn to produce CO2 and H2O.
They dissolve in water to form neutral solutions.
They react with Sodium to form Alkoxides (functional group -ONa).
They can be used as solvents to dissolve other things

Question 16

alcohols

Answer 16

Carboxylic acids react with carbonates to produce a salt, CO2 and water.
Eg: Sodium Carbonate + Ethanoic Acid –> Sodium Ethanoate + CO2 + H2O
Eg: Calcium Carbonate + Propanoic Acid –> Calcium Propanoate + CO2 + H2O
Carboxylic acids dissolve in water to produce weak acids. [1]
Carboxylic acids are used to make soaps and detergents.

Question 17

reactionsn

Answer 17

Acid + Metal -> Salt + Hydrogen
Acid + Metal Hydroxide -> Salt + Water
Acid + Metal Oxide -> Salt + Water
Acid + Metal Carbonate -> Salt + Water + Carbon Dioxide

Question 18

reactivity

Answer 18

Potassium
Sodium
Calcium
Magnesium
Aluminium
CARBON
Zinc
Iron
Tin
Lead
HYDROGEN
Copper
Silver
Gold
Platinum

Question 19

how to remember reactivity

Answer 19

Please stop calling me a cute zebra, I like her call (me) smart goat.

Question 20

carbon and metals

Answer 20

Metals higher than Carbon are extracted by electrolysis of molten compounds (similarly, more on electrolysis in that tutorial). This is far more expensive. It is also crucial to remember that in electrolysis, the less reactive cation will be reduced at the cathode. So, in an aqueous solution of Zn(NO3)2, where there are both Zn2+ and H+ ions, the more reactive Zinc ions will prefer to stay in their ionic state, whilst the less reactive H+ ions will gain electrons and be released as H2 gas.

Question 21

what are acids

Answer 21

h+

Question 22

bases

Answer 22

oh-

h + acceptors

Question 23

d. chlorine

Answer 23

– damp blue litmus paper turns red and then is bleached (paper turns
white)

Question 24

hydrogen –

Answer 24

explodes with a ‘squeaky pop’ when a burning splint is held at the open end of a test tube

Question 25

c. carbon dioxide

Answer 25

– limewater turns cloudy when shaken with the gas

Question 26

b. oxygen –

Answer 26

relights a glowing splint

Question 27

a. Al

3+, Ca2+ and Mg2+

Answer 27

each form a white precipitate.

Question 28

b. Cu2+

Answer 28

forms a blue precipitate.

Question 29

c. Fe2+

Answer 29

forms a green precipitate.

Question 30

d. Fe3+

Answer 30

forms a brown precipitate.

Question 31

flame tests

Answer 31

Li (crimson red), Na (yellow-orange), K (lilac), Ca (red-orange), Cu (green)

Question 32

anhydrous copper(II) sulfate

Answer 32

(colour change from white to blue)

Question 33

a. carbonates –

Answer 33

using a dilute acid

Question 34

b. halides –

Answer 34

using an aqueous solution of silver nitrate in the presence of dilute
nitric acid (chlorides form a white precipitate; bromides form a cream precipitate;
iodides form a yellow precipitate)

Question 35

c. sulfates –

Answer 35

using an aqueous solution of barium chloride in the presence of dilute
hydrochloric acid