Middle term test

Section :A Attempt allquestions

1.Wat is the symbol for ion with 19 protons and 18 electrons.

a)Fe⁺                b)F^–                                 c) K⁺               d)Cl^–   

2.Fe₂ (SO₄  )₃  is called…………………………….

a)Iron sulphate                       b) Iron(II) sulphate                       

1. c) Iron(III) sulphate     d) Diiron trisulphate

3.When a solid is converted  directly  to a gas , the change of state is called ?

a)Freezing                                          b)Melting           

c)Sublimation                                  d)condensation  

4.Isotopes are atoms of the same element that have ?

a)Different atomic number

b)The same atomic numbers but different number of protons

1. c) The same atomic numbers but different number of protons
2. d) The same atomic numbers but different number of neutrons

5.If a material    has  the capacity to behave either as an acidic or a base it is said to be:

a)Amorphous                       b)Amphoteric               c)Anhydrous                 d)Alkaline

   6.Calculate percentage composition by mass of oxygen and hydrogen from

the compound Na2CO3 .10H2O (Na=23, C=12, O=16, H=1)

7.A compound has the following composition 69.42% Carbon,4.13 %hydrogen and

the rest is Oxygen.

a)Determine the empirical formula of the compounds /4Marks

b)If the relative molecular mass is 242,determine its molecular formula (C=12,H=1

,O=16) /2Marks