Ordinary level 2024 South West mock chemistry 1
Ordinary level 2024 South West mock chemistry 1
What is ihc change of stale from gas to solid called?
A. Sublimation
B. Melting
C. Condensation
D. Deposition
2. Metals are malleable because
A. They have mobile electrons
B. The have strong metallic bond
C. Their atoms arc in layers
D. Layers of metal atoms can slide over each
other
3 . What is the composition of oxygen in air?
A. 0.93%
B. 0.03%
C. 78%
D. 21%
4 . A pure substance that cannot be broken down into
simpler substances is
A. A molecule
? B. An element
C. A mixture
Questions 8-11 concern the statement below.
The element X with isotopes ?£X and has relative abundances
of 64% and 36% respectively.
8. Deduce the neutron number of the two isotopes.
A. 16 and 16
tB. 15 and 17
C. 16 and 15
D. 16 and 17
9. What is the relative atomic mass of X?
A. 15.00
B. 16.72
, C. 31.72
D. 32.28
10. What type of bonding will occur when X forms an oxide with
oxygen?
;r A. Covalent
B. Ionic
C. Metallic
D. Hydrogen
11. Why is calcium chloride used ns a drying agent?
A. It is anhydrous
B. It is efflorescent
C. It is deliquescent
f D. It is hygroscopic
Questions 12–13 concern the following conversions
C2H6
1
D. A compound
5. Identity a crystalline allotrope of sulphur
A. Colloidal sulphur
B. Plastic sulphur
.C. Rhombic sulphur
D. Flowers of sulphur
6. Which of the following processes undergoes a physical
change?
tc
C2H4 C2H5OH JL ^CIljCOOH
12. State the reaction condition represented by b .
A. Cone. H7.SO4 in excess
B. Dil. H2SO4 in excess
C. Cone. HC1 in excess
* D. Cone. H2SO4 /K2CT2O7
13. Identify the reagent c
A. Ch
j B. H2
C. Pt
D. Ni
14. From the thermochemical equation
CiHsOHfg) + Chfg) –> CO:(g) –* HiOO) AVI « – 1339KJ
What docs the negative sign of AH signify?
* A. Heat is evolved
B. Reaction is endothermic
C. Heat flows from the surrounding to system
D. The reaction is not reversible
A. Heating sugar
B. Burning paper
<C . Burning candle wax
D. Burning wood
7. Sodium chloride allows current to pass through it,
because it is
A. A conductor
B. A non–conducior
* C. An electrolyte
•
D. A non-clectrolytc
