Unit 1: Basic Concepts of Chemistry

Question 1

What are the dimensions of physical quantities?

Answer 1

mass, length, and time

Question 2

How are fundamental units represented?

Answer 2

Mass [M], Length [L], Time [T]

Question 3

A ________________ indicates the contribution of fundamental units to a physical quantity’s units.

Answer 3

dimensional formula

Question 4

Why are dimensional formulas important?

Answer 4

They provide a systematic method to represent dimensions of physical quantities using fundamental units.

Question 8

What is a physical quantity in chemistry?

Answer 8

mass, length, time, temperature.

Question 8

What do dimensional formulas help explain?

Answer 8

They help explain how physical quantities are derived from mass, length, and time.

Question 9

What does a physical quantity consist of?

Answer 9

Each physical quantity has a numerical value and a unit

Question 10

_______________ are classified into fundamental units and derived units.

Answer 10

Units

Question 11

What are fundamental units?

Answer 11

Fundamental units cannot be derived from other units; there are seven recognized fundamental units.

Question 12

Give an example of a physical quantity and its unit.

Answer 12

Example: Mass - 44 Kilogram.

Question 13

_______________ is the measure of the extent of a two-dimensional surface.

Answer 13

Area

Question 14

What is the SI unit and dimensional formula for volume?

Answer 14

SI unit: cubic meter (m³); Dimensional formula: [M^0 L^3 T^0].

Question 15

How is density calculated and what are its dimensions?

Answer 15

Density = Mass/Volume; Dimensions are [M^0 L^{-3} T^0].

Question 16

What is the dimensional formula for acceleration?

Answer 16

The dimensional formula for acceleration is [M^0 L T^{-2}].

Question 17

What is specific gravity and does it have dimensions?

Answer 17

Specific gravity is the ratio of a material’s density to water’s density; it has no dimensions.

Question 18

Which tool would you use to measure mass?

Answer 18

Balance

Question 19

What does SI stand for in the context of units?

Answer 19

International System of Units

Question 20

Which of the following is an example of a fundamental unit?

Answer 20

Meter

Question 21

What is a physical quantity?

Answer 21

A measurable property of a physical system

Question 22

Explain the difference between fundamental units and derived units.

Answer 22

Fundamental Units: Basic measurements (e.g., meter, kilogram) that define physical quantities.
Derived Units: Combinations of fundamental units (e.g., Newton, Joule) used to express other measurements.

Question 23

What are the seven fundamental units in the SI system?

Answer 23

The seven fundamental units in the SI system are:

Meter (length)
Kilogram (mass)
Second (time)
Ampere (electric current)
Kelvin (temperature)
Mole (amount of substance)
Candela (luminous intensity)

Question 24

Describe the role of units in measuring physical quantities.

Answer 24

Units provide a standard way to quantify physical quantities, allowing for clear communication and comparison. They define the scale and context of measurements, ensuring consistency in scientific calculations and everyday use. Examples include meters for length, kilograms for mass, and seconds for time.

Question 25

Which tool is most appropriate for measuring the mass of the chemical sample?

Answer 25

Electronic scale

Question 26

Why is it important to use SI units in measurements?

Answer 26

To maintain consistency and standardization globally

Question 27

What is the speed of the toy car, and which unit should be used to express this physical quantity?

Answer 27

The speed of the toy car is 2.5 meters per second (m/s), calculated by dividing distance (5 m) by time (2 s).

Question 28

A physics student is conducting an experiment to measure the speed of a toy car rolling down an incline. She records the distance traveled as 5 meters and the time taken as 2 seconds. She needs to calculate the speed and present it with the appropriate unit.

Answer 28

An example of a physical quantity is force, measured in newtons (N).

Question 29

A science teacher, Ms. Adams, is conducting a lab experiment with her students to measure various physical quantities. They are using a meter stick for length, an electronic scale for mass, and a graduated cylinder for volume. However, one student mistakenly uses a thermometer to measure the volume of water.

Answer 29

The answer does not address the fundamental error of using a thermometer instead of a graduated cylinder for measuring volume.

Question 30

A physics student is conducting an experiment measuring the speed of a toy car rolling down a ramp. She notes the distance covered and the time taken to calculate the speed, which she expresses in meters per second (m/s).

Answer 30

Distance divided by time

Question 31

A physics student is conducting an experiment measuring the speed of a toy car rolling down a ramp. She notes the distance covered and the time taken to calculate the speed, which she expresses in meters per second (m/s).

Answer 31

The unit of speed is meters per second (m/s)

Question 32

A physics student is conducting an experiment to measure the speed of a moving object. She records the length of the track as 50 meters and the time taken for the object to travel this distance as 10 seconds. What fundamental quantities are used to derive speed?

Answer 32

Length and Time

Question 33

A physics student is conducting an experiment to measure the speed of a moving object. She records the length of the track as 50 meters and the time taken for the object to travel this distance as 10 seconds. Which quantity is being calculated in this experiment?

Answer 33

Speed

Question 34

How is a physical quantity expressed, and what components does it consist of?

Answer 34

A physical quantity is expressed as a combination of: Magnitude: a numerical value Unit: a standard measurement (e.g., meters, seconds) Together, they define the quantity, like "5 meters" or "10 seconds."

Question 35

In a physics lab, students are tasked with measuring the mass of various objects. They use an electronic scale for kilograms and a graduated cylinder for volume in liters. The instructor emphasizes the importance of using SI units for consistency across experiments. Which unit would be used to measure electric current?

Answer 35

Ampere (A)

Question 36

In a physics lab, students are tasked with measuring the mass of various objects. They use an electronic scale for kilograms and a graduated cylinder for volume in liters. The instructor emphasizes the importance of using SI units for consistency across experiments. Why is it essential to use SI units in scientific measurements?

Answer 36

To ensure consistency and standardization

Question 37

Why is labeling containers important in the laboratory?

Answer 37

Labeling ensures clear identification of contents for safety and effective use.

Question 38

What personal protective equipment is essential in the lab?

Answer 38

Safety glasses must be worn at all times to prevent eye damage.

Question 39

How should you properly handle glassware like beakers and flasks?

Answer 39

Always hold them from the bottom or side walls for stability and safety.

Question 40

What should you avoid when handling glassware?

Answer 40

Avoid holding glassware from the topmost side to ensure safety and stability.

Question 41

What is a critical practice when washing glass pipettes and burettes?

Answer 41

Ensure the ends do not touch the sink to prevent breakage.

Question 42

What are the minimum PPE requirements in a laboratory?

Answer 42

Lab coat, gloves, eye protection, long pants, and closed-toe shoes are mandatory.

Question 43

What risks are associated with glassware in laboratories?

Answer 43

Glassware can fracture, leading to injuries and contamination from hazardous materials.

Question 44

What should you do with cracked or contaminated glassware?

Answer 44

Cracked glassware should be disposed of; contaminated glassware must be cleaned before reuse.

Question 45

How should broken glassware be disposed of?

Answer 45

It should be discarded in a designated container for glass disposal after removing hazards.

Question 46

What type of glassware should be used for heating?

Answer 46

Only borosilicate glassware designed for heating or rapid temperature changes should be used.