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chemistry MCQs

9th • Chapter 12

50 Questions TextBook
1

Science is a systematic study of the world through observation and what other process?

A
Hypothesis
B
Experimentation
C
Guesswork
D
Philosophy
2

What is the primary reason scientists have agreed to adopt SI units?

A
They are traditional units
B
To make conversions difficult
C
They are standard and user-friendly
D
They are only used in Europe
3

SI units use a base number for easy conversion, just like our number system. What is that base number?

A
2
B
8
C
10
D
16
4

Which system of units is used almost everywhere in the world, allowing scientists to use a single standard for exchanging data?

A
CGS System
B
MKS System
C
Imperial System
D
SI System
5

Using SI units enables scientists to compare results, replicate experiments, and benefit from each other's work, which advances the frontiers of what?

A
Knowledge
B
Wealth
C
Culture
D
Politics
6

How many base units are there in the SI system for physical quantities?

A
Five
B
Six
C
Seven
D
Ten
7

Which of the following is the standard unit of length in the SI system?

A
Foot
B
Yard
C
Metre
D
Inch
8

The kilogram (kg) is the standard unit of what physical quantity?

A
Length
B
Time
C
Mass
D
Temperature
9

A kilogram is also defined as the mass of what volume of water?

A
100 cm³
B
500 cm³
C
1000 cm³
D
10 cm³
10

What is the standard unit of time in the SI system, symbolized by 's'?

A
Minute
B
Hour
C
Second
D
Day
11

The unit 'second' is based on the radiation cycles of which atom?

A
Helium-4
B
Carbon-12
C
Cesium-133
D
Uranium-235
12

What is the standard unit of temperature in the SI system, represented by K?

A
Celsius
B
Fahrenheit
C
Kelvin
D
Rankine
13

The Kelvin is defined as 1/273rd of the thermodynamic temperature of what?

A
The boiling point of water
B
The freezing point of water
C
The triple point of water
D
The critical point of water
14

What is the base unit for the amount of a pure substance, denoted by 'mol'?

A
Gram
B
Mole
C
Dozen
D
Particle
15

A mole is defined as having exactly how many particles of a substance?

A
6.022 x 10²⁰
B
3.141 x 10²³
C
6.022 x 10²³
D
1.602 x 10⁻¹⁹
16

Which of the following is a derived unit in the SI system?

A
Meter (m)
B
Kilogram (kg)
C
Second (s)
D
Cubic meter (m³)
17

What is the derived unit for density in the SI system?

A
kg per meter
B
kg per square meter
C
kg per cubic meter
D
g per cubic centimeter
18

The unit for force, Newton (N), is derived from which combination of base units?

A
kg·m·s⁻¹
B
kg·m·s⁻²
C
kg·m²·s⁻²
D
kg·m⁻¹·s⁻²
19

What does the SI prefix 'kilo' (k) represent?

A
10³
B
10⁶
C
10⁻³
D
10⁻²
20

Which SI prefix represents the fraction 10⁻³?

A
Deci
B
Centi
C
Milli
D
Micro
21

For what reason do chemists often measure the masses of reactants in grams?

A
It is the official SI unit for mass
B
Molar mass is expressed in grams per mole
C
Grams are larger than kilograms
D
It is less accurate
22

Why is the Celsius scale often used in chemistry instead of the Kelvin scale?

A
It is the official SI unit
B
It is more convenient and compatible with the base ten system
C
It has more divisions than Kelvin
D
It is harder to convert to Kelvin
23

What unit of volume is typically used in a chemistry lab for smaller quantities?

A
Cubic meter
B
Liter
C
Cubic centimeter
D
Gallon
24

The level of uncertainty that every measurement carries is known as what?

A
Error
B
Precision
C
Accuracy
D
Certainty
25

An error can occur due to the limitation of the measuring instrument or the skill of the person making the measurement?

A
True
B
False
C
Only due to instruments
D
Only due to skill
26

What type of error affects the accuracy of a measurement and can be removed by a constant adjustment?

A
Random error
B
Systematic error
C
Parallax error
D
Human error
27

A pipette or burette delivering a volume slightly different from its graduation is an example of what kind of error?

A
Random error
B
Procedural error
C
Systematic error
D
Observational error
28

What type of error comes from unpredictable changes during an experiment and causes one measurement to differ slightly from the next?

A
Systematic error
B
Constant error
C
Random error
D
Instrumental error
29

Reading a volume from a measuring cylinder from a different angle each time is an example of a?

A
Systematic error
B
Random error
C
Zero error
D
Calibration error
30

A random error often determines the what of the experiment?

A
Accuracy
B
Outcome
C
Precision
D
Hypothesis
31

What term measures how close results are to the true or known value?

A
Precision
B
Reliability
C
Reproducibility
D
Accuracy
32

The closeness of two or more measurements to each other is known as?

A
Accuracy
B
Precision
C
Correctness
D
Certainty
33

If you weigh a substance five times and get 3.2 kg each time, your measurement is considered what?

A
Accurate
B
Precise
C
Both accurate and precise
D
Neither accurate nor precise
34

Can a measurement be precise but not accurate?

A
Yes
B
No
C
Only in physics
D
Only with digital tools
35

A student measures an object with a true mass of 20g and gets readings of 19.8, 20.5, and 19.6. This student is considered more?

A
Precise but not accurate
B
Accurate but not precise
C
Both accurate and precise
D
Neither accurate nor precise
36

Which of the following pairs of quantities can be measured in the same unit?

A
Heat and temperature
B
Temperature and area
C
Heat and work
D
Length and work
37

What is the SI unit of pressure?

A
Newton per metre
B
Joule
C
Pascal
D
Newton per gram
38

The symbol for kilogram in SI units is?

A
K
B
Kgm
C
kg
D
kG
39

What does a mole (mol) represent?

A
Number of particles
B
Mass
C
Volume
D
Length
40

Which prefix is used for 10⁻⁹?

A
Nano
B
Micro
C
Pico
D
Giga
41

What does the prefix 'Mega' (M) stand for?

A
10³
B
10⁶
C
10⁹
D
10⁻⁶
42

The derived unit for area in the SI system is?

A
Square centimeter
B
Square meter
C
Hectare
D
Acre
43

Pressure is expressed in Pascals (Pa), which is equivalent to what?

A
N·m
B
N·m⁻¹
C
N·m⁻²
D
N·m²
44

The unit for energy, Joule (J), is equivalent to?

A
N·m⁻¹
B
N·m
C
Pa·m³
D
kg·m·s⁻¹
45

Which error may occur due to limitations of instruments, environmental factors, and slight variations in procedure?

A
Systematic error
B
Gross error
C
Personal error
D
Random error
46

Which of the following is NOT one of the five base SI units commonly used in chemistry?

A
Length
B
Time
C
Mass
D
Volume
47

According to the text, why is it sensible to use grams rather than kilograms in a chemistry lab?

A
It is the official SI base unit
B
It provides more manageable numbers for calculation
C
It is more accurate than kilograms
D
It is required by international law
48

What is defined as the distance travelled by light in a vacuum in about 1/300,000,000 of a second?

A
Kilometer
B
Centimeter
C
Metre
D
Mile
49

The 'triple point of water' is a state where?

A
Water is boiling
B
Water is frozen solid
C
Water is in a plasma state
D
All three states of water exist at the same time
50

Why did scientists adopt a common system of units like SI?

A
To make science more exclusive
B
To ensure everyone can understand each other's measurements
C
To follow a historical tradition
D
To make calculations more complex