Physical and Chemical Properties:JEE/NEET/Class 11 CBSE Notes

ANAND CLASSES Study Material and Notes to learn Comprehensive notes on Physical and Chemical Properties for JEE, NEET, and Class 11 CBSE. Includes definitions, differences, examples, MCQs, and worksheets for effective exam preparation.

🔍 Physical and Chemical Properties

❓Q1. What are physical and chemical properties of substances?

✅Answer:
Every substance has its unique or characteristic properties that help us identify, describe, and differentiate it from other substances. These properties are broadly classified into:

1. Physical Properties
2. Chemical Properties

Both play a vital role in understanding the nature and behaviour of matter.

🔷 PHYSICAL PROPERTIES

❓Q2. What are physical properties?

✅Answer:
Physical properties are those characteristics of a substance that can be measured or observed without altering the chemical nature or composition of the substance.

❓Q3. What are some common examples of physical properties?

✅Answer:

• Colour: e.g., Copper is reddish-brown.
• Odour: e.g., Ammonia has a pungent smell.
• Melting Point: Temperature at which a solid turns into liquid.
• Boiling Point: Temperature at which a liquid changes to vapour.
• Density: Mass per unit volume of a substance.
• Solubility: Ability to dissolve in a solvent.
• Hardness: Resistance to scratching.

❓Q4. Why are physical properties important?

✅Answer:
They help in:

• Identifying and classifying substances.
• Determining suitable uses (e.g., metals for construction due to hardness).
• Understanding changes in physical state (e.g., melting, boiling).

🔁 Example:

• Ice melting into water is a physical change. The state changes, but the substance (H₂O) remains the same.
• Water boiling is another physical process; only its state changes.

🔶 CHEMICAL PROPERTIES

❓Q5. What are chemical properties?

✅Answer:
Chemical properties describe the ability of a substance to undergo a specific chemical change and form new substances with different compositions.

❓Q6. Can chemical properties be observed without a chemical reaction?

✅Answer:
No. Chemical properties can be observed only when the substance undergoes a chemical change or reaction.

❓Q7. What are some common examples of chemical properties?

✅Answer:

• Combustibility: Ability of a substance to burn in oxygen (e.g., gasoline is combustible).
• Reactivity with acids/bases: e.g., Zinc reacts with hydrochloric acid to produce hydrogen gas.
• Acidity/Basicity: Nature of the substance – acidic or basic.
• Oxidation/Reduction tendencies: e.g., iron rusting.

🔁 Example:

• Burning of wood → wood + O₂ → CO₂ + ash + heat
  This is a chemical change, and combustibility is the chemical property.

⚖️ DIFFERENCE BETWEEN PHYSICAL AND CHEMICAL PROPERTIES:

🎯 Application in JEE/NEET:

Understanding these properties helps in:

• Predicting reactions (e.g., which metal will react with acid).
• Classifying elements and compounds.
• Balancing chemical equations.
• Identifying physical vs chemical changes in lab experiments.

📌 Quick Revision Points:

• Physical properties do not change the composition of a substance.
• Chemical properties involve formation of new substances.
• Combustibility, acidity, and reactivity are chemical.
• Colour, density, and melting point are physical.

💡 “Do You Know?” Facts:

• Mercury is the only metal that is liquid at room temperature – a physical property.
• Sodium reacts explosively with water – a chemical property!
• Rusting of iron is a slow chemical change involving oxidation.

🧠 MCQs on Physical and Chemical Properties

✅ MCQ 1:

Which of the following is a physical property of a substance?

A) Combustibility
B) Reactivity with acid
C) Melting point
D) Oxidation

✔ Correct Answer: C) Melting point

📝 Explanation:
Melting point is a physical property because it can be measured without changing the chemical composition of the substance. The other options (combustibility, reactivity, oxidation) involve chemical changes.

✅ MCQ 2:

Which of the following is a chemical property?

A) Boiling point
B) Density
C) Odour
D) Reactivity with oxygen

✔ Correct Answer: D) Reactivity with oxygen

📝 Explanation:
Reactivity with oxygen is a chemical property because it leads to a chemical reaction, often forming a new substance (e.g., rusting of iron). Boiling point, density, and odour are physical properties.

✅ MCQ 3:

Rusting of iron is an example of which type of change and property?

A) Physical change and physical property
B) Physical change and chemical property
C) Chemical change and physical property
D) Chemical change and chemical property

✔ Correct Answer: D) Chemical change and chemical property

📝 Explanation:
Rusting is a chemical change where iron reacts with oxygen and moisture to form iron oxide (rust). The property that allows this to happen (reactivity with oxygen) is a chemical property.

✅ MCQ 4:

Which of the following processes does NOT involve a chemical change?

A) Burning of candle
B) Boiling of water
C) Rusting of iron
D) Digestion of food

✔ Correct Answer: B) Boiling of water

📝 Explanation:
Boiling of water is a physical change (liquid to gas) and does not change the chemical composition of water (H₂O). The other processes involve formation of new substances, hence are chemical changes.

✅ MCQ 5:

Which of these is an example of both a physical and a chemical change happening simultaneously?

A) Burning of wood
B) Melting of wax
C) Dissolving salt in water
D) Cutting of paper

✔ Correct Answer: A) Burning of wood

📝 Explanation:
Burning of wood includes:

• Physical change: Release of gases, water vapor
• Chemical change: Formation of new substances like carbon dioxide, ash
  So it’s both a physical and chemical change.

✅ MCQ 6:

Which of the following is NOT a chemical property?

A) Ability to burn
B) Ability to react with acid
C) Ability to corrode
D) Ability to conduct electricity

✔ Correct Answer: D) Ability to conduct electricity

📝 Explanation:
Electrical conductivity is a physical property, as it doesn’t involve any chemical change. The rest involve chemical reactions or formation of new substances.

✅ MCQ 7:

Which property can be used to identify a substance without changing its chemical nature?

A) Flammability
B) Acidity
C) Boiling point
D) Reactivity with base

✔ Correct Answer: C) Boiling point

📝 Explanation:
Boiling point is a physical property and helps in identifying substances without altering their chemical identity.

📝 Worksheet: Physical and Chemical Properties

🧠 Part A: Multiple Choice Questions (MCQs)

Choose the correct option.

1. Which of the following is a chemical property?
   A) Colour
   B) Density
   C) Reactivity with oxygen
   D) Melting point
2. Which process represents a physical change only?
   A) Burning of magnesium
   B) Melting of ice
   C) Rusting of iron
   D) Digestion of food
3. Which property helps in identifying a substance without changing its chemical nature?
   A) Reactivity with base
   B) Flammability
   C) Boiling point
   D) Acidity
4. Which of the following involves a chemical change?
   A) Sublimation of iodine
   B) Evaporation of alcohol
   C) Burning of LPG
   D) Dissolution of sugar in water
5. Which of the following is a physical property of copper?
   A) Reactivity with acid
   B) Formation of green patina on exposure to air
   C) Reddish-brown colour
   D) Corrosion

✍️ Part B: Fill in the Blanks

6. __________ is the ability of a substance to undergo combustion in the presence of oxygen.
7. Properties that can be observed without a chemical change are called __________ properties.
8. Rusting of iron is a __________ change and depends on the __________ property of iron.
9. Melting, boiling, and freezing points are all examples of __________ properties.
10. Acidity and basicity are classified as __________ properties.

✅ Part C: True or False

11. Colour is a chemical property.
12. Chemical properties can be observed without changing the substance.
13. Reactivity with acids is a chemical property.
14. Melting of ice is a physical change.
15. Flammability is a chemical property.

✍️ Part D: Short Answer Questions

16. Define physical and chemical properties with two examples each.
17. Why is burning of paper considered a chemical change?
18. Differentiate between physical and chemical changes with any two points.
19. Give one example of a property that is both physical and useful in industrial applications.
20. Explain how chemists use physical and chemical properties to identify substances.

🧾 Answer Key (for teacher/parent reference):

Part A: MCQs

1. C
2. B
3. C
4. C
5. C

Part B: Fill in the Blanks

6. Combustibility
7. Physical
8. Chemical, chemical
9. Physical
10. Chemical

Part C: True or False

11. False
12. False
13. True
14. True
15. True

Part D: Sample Answers

• Physical Properties: Can be observed without changing composition.
  e.g., colour, melting point
• Chemical Properties: Require a chemical reaction to observe.
  e.g., combustibility, acidity

17. Burning of paper forms new substances like carbon dioxide and ash, indicating a chemical change.

19. Melting point – helps in purification and processing of metals in industries.
20. Chemists use properties to classify, predict reactions, identify unknown substances, and design chemical processes.