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