12
Chapter 12· Empirical Data Collection and Analysis
MCQs with Answers Try each one first: tap an option to check it, then read the reasoning and why the others are wrong.
A note about the questions
The wording follows published solved exercises and every answer was re-checked by hand, so the wording or the order of options may differ slightly from your print.
Answered 0 of 24 · Correct 0
Set A: Textbook exercise 10 MCQs The multiple-choice questions at the end of Chapter 12 in your book, in the book's option order.
Q12.1 Base and Derived Units
Which of the following pairs of quantities may be measured in the same unit?
(a) Heat and temperature (b) Temperature and area (c) Heat and work (d) Length and work Show answer and reasoning Answer (c) Heat and work
Step by step
Heat → joule. Work → joule (N m). Why the others are wrong
(a) heat is in joules, temperature in kelvin (or °C).(b) kelvin and square metre.(d) metre and joule.Remember
Energy family (heat, work, energy) = joule.
Q12.2 Prefixes and Practical Units
In which unit we usually measure the energy present in the food?
(a) Kilojoules (b) Megajoules (c) Calorie (d) Joule Show answer and reasoning Answer (a) Kilojoules
Step by step
A slice of bread ≈ 300 kJ. kilo = 10³, a manageable number. Why the others are wrong
(b) far too large for one food item.(c) Calories (kcal) are also printed, but the Calorie is not an SI unit.(d) too small; numbers would run into hundreds of thousands.Q12.3 Prefixes and Practical Units
What prefix is used for 10⁻¹²?
(a) Mega (b) Pico (c) Giga (d) Tessa Show answer and reasoning Answer (b) Pico
Step by step
milli 10⁻³, micro 10⁻⁶, nano 10⁻⁹, pico 10⁻¹². Why the others are wrong
(a) 10⁶.(c) 10⁹.(d) no such prefix (tera is 10¹²).Remember
m-μ-n-p: every step ÷ 1000.
Q12.4 Base and Derived Units
In SI unit of pressure is expressed in:
(a) Newton per metre (b) Newton per metre square (c) Joule (d) Pascal Show answer and reasoning Answer (d) Pascal
Step by step
Pressure = force ÷ area = N ÷ m² = N m⁻² = Pa. Why the others are wrong
(a) N m⁻¹ is not pressure (force per length).(b) as a choice: it equals 1 Pa, but the SI unit is named the pascal.(c) joule is energy.Remember
Pressure → Pascal.
Q12.5 Base and Derived Units
Which symbol is used for kilogram in SI units?
Show answer and reasoning Answer (d) kg
Step by step
k (kilo) + g (gram) = kg. Why the others are wrong
(a) kelvin.(b) only the prefix kilo.(c) not an SI symbol.Remember
Small k, small g.
Q12.6 Base and Derived Units
What does a mole represent?
(a) Number (b) Mass (c) Volume (d) Length Show answer and reasoning Answer (a) Number
Step by step
1 mol = 6.022 × 10²³ particles (Avogadro's number). Why the others are wrong
(b) molar mass is the mass of one mole.(c) molar volume is the volume of one mole of gas.(d) Wrong.Remember
Mole = chemist's dozen.
Q12.7 Prefixes and Practical Units
Which unit of volume should usually be used in Chemistry?
(a) Millilitre (b) Litre (c) Cubic centimetre (d) Cubic metre Show answer and reasoning Answer (c) Cubic centimetre
Step by step
A burette holds 50 cm³; 1 m³ = 1 000 000 cm³. Why the others are wrong
(a) same volume as cm³, but the book names cm³.(b) too large for most lab work.(d) far too large.Remember
Lab glassware is marked in cm³.
Q12.8 Prefixes and Practical Units
Express 0.000840 in scientific notation:
(a) 8.40 × 10⁻³ (b) 840 × 10⁻⁶ (c) 8.40 × 10⁻⁴ (d) 84.0 × 10⁻⁵ Show answer and reasoning Answer (c) 8.40 × 10⁻⁴
Step by step
0.000840 → 8.40 (4 places right). So 8.40 × 10⁻⁴. Why the others are wrong
(a) that is 0.00840.(b) equal value but 840 is not between 1 and 10.(d) equal value but 84.0 is not between 1 and 10.Remember
Count the jumps to the first non-zero digit.
Q12.9 Prefixes and Practical Units
In SI units prefix nano means:
(a) 10⁻⁹ (b) 10⁻⁸ (c) 10⁻¹¹ (d) 10⁻¹² Show answer and reasoning Answer (a) 10⁻⁹
Step by step
Table 12.4: nano n 10⁻⁹. Why the others are wrong
(b) no prefix.(c) no prefix.(d) pico.Q12.10 Prefixes and Practical Units
65 °C is equivalent to:
(a) 208 K (b) 338 K (c) 403 K (d) 300 K Show answer and reasoning Answer (b) 338 K
Step by step
K = °C + 273. 65 + 273 = 338. Why the others are wrong
(a) that subtracts 65 from 273.(c) 403 K is 130 °C.(d) 300 K is 27 °C.Remember
Kelvin is always 273 more.
Set B: More MCQs from this chapter 14 MCQs Extra questions on the same ideas, of the kind set in board papers and class tests.
QB1 SI Units and Their Need
How many base units are there in the SI system?
(a) Five (b) Seven (c) Nine (d) Twenty-two Show answer and reasoning Answer (b) Seven
Step by step
7 base units; 5 used in chemistry. Why the others are wrong
(a) that is how many chemistry uses.(c) Wrong.(d) that is the number of named derived units.Remember
Seven base, five for chemistry.
QB2 Base and Derived Units
How many of the SI base units are generally used in Chemistry?
(a) Three (b) Four (c) Seven (d) Five Show answer and reasoning Answer (d) Five
Step by step
m, s, mol, kg, K. Why the others are wrong
(a) Wrong.(b) Wrong.(c) that is the whole SI set.Remember
Chemistry leaves out the ampere and candela.
QB3 Base and Derived Units
The SI unit of amount of substance is:
(a) gram (b) kilogram (c) mole (d) litre Show answer and reasoning Answer (c) mole
Step by step
Amount of substance → mol. Why the others are wrong
(a) mass.(b) mass.(d) volume.Remember
Amount = mole; mass = kg.
QB4 Base and Derived Units
The kelvin is defined as what fraction of the thermodynamic temperature of the triple point of water?
(a) 1/100 (b) 1/273.16 (c) 1/373 (d) 1/1000 Show answer and reasoning Answer (b) 1/273.16
Step by step
Triple point = 273.16 K = 0.01 °C. Why the others are wrong
(a) that is one degree on a 0-100 scale.(c) 373 K is the boiling point.(d) Wrong.Remember
Triple point: 273.16.
QB5 Base and Derived Units
The second is defined by the radiation of which atom?
(a) Sodium (b) Mercury (c) Hydrogen (d) Caesium-133 Show answer and reasoning Answer (d) Caesium-133
Step by step
Atomic clocks use caesium-133. Why the others are wrong
(a) Wrong.(b) Wrong.(c) Wrong.QB6 Errors in Measurement
Which error may be removed by adding or subtracting a constant adjustment to each measurement?
(a) Systematic error (b) Random error (c) Personal error (d) Accidental error Show answer and reasoning Answer (a) Systematic error
Step by step
Same shift each time → one correction fixes all. Why the others are wrong
(b) it changes from reading to reading; it is reduced by averaging.(c) careless mistakes are not fixed by one constant.(d) another name for random error.Remember
Systematic = same each time.
QB7 Errors in Measurement
A random error mainly determines the:
(a) unit of the result (b) precision of the experiment (c) true value (d) number of base units Show answer and reasoning Answer (b) precision of the experiment
Step by step
Random → scatter → precision. Systematic → shift → accuracy. Why the others are wrong
(a) Wrong.(c) the true value does not depend on our errors.(d) Wrong.QB8 Prefixes and Practical Units
A room temperature of 25 °C on the kelvin scale is:
(a) 248 K (b) 273 K (c) 298 K (d) 300 K Show answer and reasoning Answer (c) 298 K
Step by step
25 + 273 = 298. Why the others are wrong
(a) subtracted.(b) that is 0 °C.(d) that is 27 °C.QB9 Prefixes and Practical Units
One cubic decimetre (1 dm³) is equal to:
(a) 10 cm³ (b) 100 cm³ (c) 1000 cm³ (d) 10 000 cm³ Show answer and reasoning Answer (c) 1000 cm³
Step by step
(10 cm)³ = 1000 cm³. Why the others are wrong
(a) forgot to cube.(b) squared only.(d) Wrong.Remember
Cube the factor, not just the number.
QB10 Base and Derived Units
The SI unit of density is:
(a) kg m⁻³ (b) kg m⁻² (c) kg m (d) N m⁻² Show answer and reasoning Answer (a) kg m⁻³
Step by step
kg / m³ = kg m⁻³. Why the others are wrong
(b) mass per area.(c) Wrong.(d) that is pressure.Remember
Volume is cubed: m⁻³.
QB11 Prefixes and Practical Units
5 mg expressed in grams is:
(a) 5 × 10⁻³ g (b) 5 × 10⁻⁶ g (c) 5 × 10³ g (d) 0.5 g Show answer and reasoning Answer (a) 5 × 10⁻³ g
Step by step
m = 10⁻³. Why the others are wrong
(b) that is micro.(c) that is kilo.(d) that is 500 mg.Remember
Replace the prefix by its power of ten.
QB12 Accuracy and Precision
The exact mass of an object is 20 g. A student records 17.3 g, 17.4 g and 17.2 g. The readings are:
(a) accurate and precise (b) accurate but not precise (c) neither accurate nor precise (d) precise but not accurate Show answer and reasoning Answer (d) precise but not accurate
Step by step
Spread 17.2-17.4 → precise. Mean 17.3 ≠ 20 → not accurate. Why the others are wrong
(a) far from 20 g.(b) the reverse.(c) they are close together.Remember
Close together = precise; close to true = accurate.
QB13 Prefixes and Practical Units
The symbol of the prefix micro (10⁻⁶) is:
Show answer and reasoning Answer (d) μ
Step by step
μ = 10⁻⁶. Why the others are wrong
(a) milli.(b) mega.(c) nano.Remember
μ for micro, m for milli.
QB14 Base and Derived Units
A pressure of 1 pascal is equal to:
(a) 1 N m (b) 1 N m⁻² (c) 1 J m (d) 1 kg m s⁻² Show answer and reasoning Answer (b) 1 N m⁻²
Step by step
P = F/A. Why the others are wrong
(a) that is a joule.(c) Wrong.(d) that is a newton.Remember
Per square metre: m⁻².
