Page 32 - Focus SPM KSSM F4 2020 - Chemistry

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Chapter B – The solution/ liquid chemical Section B
should not be sucked using the
1 Introduction to Chemistry mouth. A pipette should be used 2. (a) • Hypothesis is a statement
to suck up the solution/ liquid that links the manipulated
variable to the responding
chemical into the apparatus. variable. [1]
Checkpoint 1.1 Q3 He should remove his laboratory • Manipulated variable is
Q1 Chemistry is a branch of science coat immediately. If the acid wets his the factor that is purposely
that studies the composition, clothes, he should rinse his whole changed in an experiment.
structure, characteristics and body under the safety shower. At the [1]
interaction of matter. same time, he should ask his friend • Responding variable is the
Q2 Iron: It is used to make nails, screws to report the incident to the teacher. factor that changes with the
[1]
manipulated variable.
and nuts; Chlorine: It is used to treat • Constant variable is the
tap water; Calcium carbonate: It is SPM Practice 1 factor that is kept constant
used as construction material/ to in an experiment. [1]
manufacture cement. Objective Questions 4
Q3 To carry out research and 1. D 2. B 3. C 4. B 5. A (b) • List out all the materials and
development of food products/ To 6. D 7. C 8. C apparatus needed to be
carry out analysis to check the used. [1]
quality of products/ To provide Subjective Questions • Determine how to control
technical support to the marketing the manipulated and
section. Section A • constant variables. [1]
Determine how to measure
1. (a) (i) Long hair that is not tied up the responding variable. [1]
Checkpoint 1.2 easily catches fire. [1] • Determine how to collect,
Q1 Make observations, make an (ii) Closed-up shoes will be analyse and interpret data.
inference, identify the problem, make able to protect the feet from [1]
a hypothesis, identify the variables, chemical spills or injury due 4
control the variables, plan and carry to glass apparatus falling (c) (i) Manipulated variable –
out an experiment, collect data, onto the feet or floor. [1] Mass of salt added to pure [1]
water.
interpret data, make a conclusion, (iii) If the excess solution is Responding variable – Time
write a report. contaminated, the action taken to freeze the water [1]
Q2 (a) The more water is added to the of pouring it back into 2
acid, the higher the pH of the its reagent bottle will (ii) The larger the mass of salt
acid. contaminate all the solution added to pure water, the longer
(b) Manipulated variable: Volume of in the bottle. [1] time it takes for the water to
water added 3 freeze. [1]
Responding variable: pH value (b) I will report the incident to the (iii) Volume of pure water used. [1]
of acid teacher immediately. Then, Type of container used. [1]
Controlled variable: Type and using gloves, I will dispose Type of freezer used. [1]
volume of acid used, pH paper of the broken test tube into (any two) 2
used a specific container that is
prepared and clean up the spill (d) (i) The larger the mass of salt
as instructed by the teacher. [3] added to pure water, the
Checkpoint 1.3
(c) A fume cupboard is a higher is its density. [1]
Q1 Goggles – to protect the eyes from cupboard where the air in it (ii) • The manipulated variable
chemicals is always being sucked out. is the mass of salt added
[1]
to pure water.
Safety shower – to remove A fume cupboard is used • So, different mass of salt
chemicals that the body comes in to carry out activities that is added to pure water, for
contact by showering all parts of the involve volatile, inflammable example 1 g, 2 g, 3 g, 4 g
body or toxic chemicals so that the and 5 g. [1]
Fire blanket – to put out the fire on a vapour from the chemicals is • The responding variable is
victim’s body disposed of immediately from the density of water. [1]
the fume cupboard and does
Q2 A – Chemicals should not be sniffed • So, he can measure the
directly. Instead, the individual not contaminate the air in the initial mass and final mass
should use his hands to waft the laboratory. [3] of each mixture of water
smell to his nose. and salt.

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10 ANSWER FOCUS KIMIA F4 SPM.indd 258 27/02/2020 11:29 AM