a)      The gas in air that support combustion is Oxygen,

b)      The gas in air that causes global warming is Carbon monoxide,

c)      The gas in air that is chemically inactive is Nitrogen,

d)      The gas in air that makes biggest part in air is Nitrogen

a)      In test –tube A, the nail will become rust because of water contained in the tube

b)      The purpose of anhydrous calcium chloride in the tube B is to absorb any moisture in the test- tube

c)      Boiled water in test used in tube C because it is free from air

a)      Melting point is the temperature at which a substance changes from solid state to liquid state

b)      Substance B will be in gas state at room temperature of 20⁰C

c)      Metal is a substance A

a)       

                                   i.            The chemical formula of sulphuric Acid is H₂SO₄

                                 ii.            The chemical formula of Sodium Phosphate is Na₃PO₄

b)      Sulphuric acid + sodium Carbonate → sodium sulphate + water + Carbone dioxide.

1.       Fe₂O₃(s) + 3 CO(g) → 2 Fe(s) +3CO₂(g)

a)      Oxidizing agent is Fe₂O₃

b)      Relative molecular mass of Fe₂O₃ = 56×2 + 16×3= 160g/mol

Relative molecular mass of Fe is 56g/mol

From the equation:

2moles of Fe generated from 1mol of Fe₂O₃

It means that (2 x 56) g of Fe → 160 g of Fe₂O₃

112g of Fe → 160 g of Fe₂O₃

Therefore, 160g of Fe₂O₃ required to produce is 112g of Fe

a)       

b)      For dilute H₂SO₄

At Cathode, Ionic equation: 2H⁺ + 2e^- →H₂

For CuSO₄ Solution at cathode, ionic equation: 2Cu²⁺ + 2e^- → Cu

a)       A: respiration

B: Photosynthesis

C: Fossilization

D: Combustion

b)      Fuel means any substance or a material used to produce heat or power by burning

c)      One example of fuel used in my home:

1)      Charcoal,

2)      Wood,

3)      Liquefied petroleum gas,

4)      Petrol 

a)      A catalyst is a chemical substance that speeds up, increase or Accelerate the rate of reaction without itself being affected.

Or

A catalyst is a chemical substance that is added to a process to make a chemical reaction happen more quickly without itself being consumed

Or

A catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

b)       

                                            i.            During the decomposition of hydrogen peroxide Manganese IV oxide (MnO₂ ) used as Catalyst

                                          ii.            The reaction between zinc and sulfuric acid need Copper II Sulphate (CuSO₄) as Catalyst

                                        iii.            In contact process, the catalyst used is Vanadium Pentoxide (V₂O₅)

a)            According to the data we have, 100g of compound contains 82.8 g of Carbon and 17.2 g of Hydrogen.

Number of moles of atoms:

·     Carbon:$\frac{82.8g ×1moles}{12g}=6.9 moles$\frac{82.8g ×1moles}{12g}=6.9 moles

·     Hydrogen:$\frac{17.2g ×1 moles}{1g}=17.2 moles$\frac{17.2g ×1 moles}{1g}=17.2 moles

                       Relative number of moles of atoms:

·     Carbon:  $\frac{6.9moles}{6.9moles}=1$\frac{6.9moles}{6.9moles}=1      

·     Hydrogen: $\frac{17.2 moles}{6.9 moles}=2.5$\frac{17.2 moles}{6.9 moles}=2.5

                           To obtain a whole number, multiply the relative number of moles of atoms by

                             integer 2

·         Carbon: 1×2= 2

·         Hydrogen: 2.5 ×2=5

                       Therefore, Empirical formula is C₂H₅

b)     Molecular formula

·         Formula: Empirical formula multiplied by n

The simplest weight: (12g×2) +( 1g×5) =29g

Molecular weight: 58g

Multiplication factor (n) will be:$\frac{molecular weight}{simplest weight}$

                                 n:$\frac{58g}{29g}=2$\frac{58g}{29g}=2

                       therefore, the molecular formula will be (C₂H₅)_2, the same to C₄H₁₀

a)      The gases that can be prepared in the laboratory using the apparatus (diagram) shown is Hydrogen (H₂ )

b)      The substance A in diagram is Zinc in solid state

The substance B in diagram is Diluted Sulfuric Acid (H₂S0₄ )

c)      Ammonia cannot be prepared with the apparatus shown because it is very soluble in water and it cannot be collected over water.

a)      The nitrate of Zinc and nitrate Copper release two gases by heating

b)      The nitrate of Potassium release one gases by heating,

The balanced equation:      

a)      Potassium(K) is more reactive compared to sodium(Na)

b)      Chlorine(Cl) is more reactive than Bromine

c)      Sodium (Na) will make ionic bond by reacting with oxygen.

d)      The electronic configuration of Potassium

1^st Method: 2,8,8,1

2^nd Method: 1s²2s²2p⁶3s²3p⁶4s¹

           3^rd Method: 

1.        

a)      2-methyl propane is isobutane or methyl propane 

b)      Acetic acid is Ethanoic acid

c)      Propanol is also known as propan-1-ol, isopropyl alcohol or n-propanol

1.       

a)      2 Al + 6 HCl → 2 AlCl₃ + 3H₂

b)      2 Al + 3 CuSO₄ → 3 Cu + Al(SO₄)₃