Gases in the Atomosphere

Question 1

What is the percentage of oxygen in the atmosphere

Answer 1

21%

Question 2

what is the percentage of nitrogen in the atmosphere

Answer 2

78%

Question 3

what is the percentage of argon in the atmosphere

Answer 3

0.9%

Question 4

what is the percentage of C02 in the atmosphere

Answer 4

0.04%

Question 5

what is the scientific word for burning

Answer 5

Combustion:

Question 6

when magnesium is burned, what colour flame and what product is produced, and what happens when that product is dissolved in water

Answer 6

Magnesium - white flame, white powdery ash - magnesium oxide
Magnesium oxide is not very soluble –> a little bit may dissolve to form magnesium hydroxide

Question 7

when sulfur is burned, what colour flame and what product is produced, and what happens when that product is dissolved in water

Answer 7

Sulfur - burns with a blue flame, sulfur dioxide (=sulfur (IV) oxide)
Sulfur dioxide = colourless and poisonous
dissolves in water to become sulfurous acid - H2SO3

Question 8

what is the difference betwen sulfurous acid and sulfuric acid

Answer 8

sulfurous is H2S03 and sulfric is H2S04

Question 9

when hydrogen is burned, what colour flame and what product is produced

Answer 9

Hydrogen - pale blue flame. produces water. Hydrogen is very very very combustible - when reacting with oxygen it results in an explosion

Question 10

what do metal oxides react with and what do they form

Answer 10

Metal oxidise react with acids to form salts

Question 11

are metal oxides soluble in water and if they are what are the produces

Answer 11

Most metal oxides are not soluble in water. The few that ARE soluble react with water to form alkaline solution with hydroxide ions, metal hydroxide

Question 12

what do nonmetal oxides react with and what do they form

Answer 12

Non-metal oxides react with alkalis/bases (this is because they are acidic oxides) to form salts

Question 13

are nonmetal oxides soluble in water and if they are what are the produces

Answer 13

Non-metal oxides are quite soluble in water
Non-metal oxides form acidic solutions containing H+ ions

Question 14

what is the general equation of metal carbonate + acid

Answer 14

metal carbonate +acid –> salt + co2 + water

Question 15

what is thermal decomposition

Answer 15

Thermal decomposition = when heat is used for the breakdown of something

Question 16

what is calcium carbonate

Answer 16

Calcium carbonate = limestone + marble

Question 17

what happens to most metal carbonates when they undergo thermal decompostition

Answer 17

When most carbonates undergo thermal decomposition this forms metal oxide and CO2

Question 18

what are the 3 greenhouse gases

Answer 18

The three greenhouse gases:
carbon dioxide
methane - CH4
water vapour

Question 19

what are the 3 fossil fuels

Answer 19

The three fossil fuels are:
Coal
Oil
Gas

Question 20

how do we get petrol

Answer 20

We get petrol from the fractional distillation of crude oil

Question 21

what do greenhouse gases do

Answer 21

Greenhouse gases ‘trap the radiation from the Sun’, but absorbing the radiation. These gases absorb the radiation and then emit it in all directions.

Question 22

what is the greenhouse effect (2)

Answer 22

The Greenhouse Effect: the process of the Earth warming up/being warm due to these gases in the atmosphere absorbing and emitting radiation.
The greenhouse gases are able to absorb radiation due to being polar molecules.

Question 23

what is polarity

Answer 23

A molecule is polar when one side is slightly more negative and the other is slightly more positive.

Question 24

how does polarity happen

Answer 24

Polarity comes about because the different atoms in the molecule attract the shared electrons to different amounts - so if one attracted it more, it becomes slightly electronegative, and so the other side of the molecule would become slightly positive.

Question 25

what can cause polarity

Answer 25

Water = polar molecule
Carbon dioxide is not naturally polar as it is a linear shape (the atoms are in a straight line)
HOWEVER, when the CO2 molecule starts to vibrate, it becomes polar, allowing it to be a greenhouse gas.
if a molecule is linear then the atoms cannot shift causes the electrons to be more on one side

Question 26

Why are N2, and O2 not greenhouse gases:

Answer 26

N2 and O2 are molecules that are made up of the same type of atoms (same elements) bonded together. This means there is no difference in how strongly they attract the electrons, so the electrons are not pulled closer to either side, so both remain uncharged and so not polar.