Ordinary level 2025 North West regional mock chemistry 2

Ordinary level 2025 North West regional mock chemistry 2

Ordinary level 2025 North West regional mock chemistry 2

ih Calculate the concentration of the acid It) mol/dm‘ if $5trr,* 0f tf« 0 ?Mf /.– ,< O. in tl. : r./mkal fh–Y. w‘n
neutralized by 2()cm1 of the add from the hurdle.
s ( 2mks)
—
An indicator is used in this experiment
iii. What is the use of an indicator?
iv. Suggest a suitable indicator for this reaction procedure and give the colour change obv:r zed
Indicator
Initial Colour
Final Colou

ANSWER ONLY TWO QUESTIONS FROM THIS SECTION. If you answer more than two questions only
the first two will be considered. Where appropriate, equations and diagrams should be used to illustrate your
answer.
8. Atoms of elements are linked by chemical bonds which could be ionic, simple covalent or metallic.
a.Define a chemical bond.
b.Using suitable examples and diagrams describe how each bond is formed.
c. State one property of each substance in (b) and relate the property to the bond type
9. a Identify the gases described below. Briefly describe how a pure dry sample of each gas can be prepared and
collected in the laboratory
i. It turns acidified potassium dichromate from orange to green without a precipitate.
ii. It is odourless, and rekindles a glowing splint