Chemistry Notes – Grade 10
National Curriculum Pakistan - NCP
Chapter 2: Matter
Aligned with National Curriculum Pakistan (Federal Board, NBF, PTB)
- What is phase transition?
A phase transition is the change of matter from one state to another, such as solid to liquid, liquid to gas, or solid directly to gas. - What is kinetic particle theory?
Kinetic Particle Theory explains phase transitions through changes in internal energy. Temperature remains constant, but potential energy changes significantly, affecting inter-particle forces. - What happens when solid melts?
The solid becomes a liquid. Particles gain enough energy to overcome attraction and move freely. - What happens when liquid boils?
It turns into gas. Particles gain energy, move faster, and break free into gas phase at constant boiling temperature. - What is freezing?
Freezing is the transition of liquid into solid as temperature drops below freezing point. - What happens when liquid freezes?
Particles lose energy, slow down, and form an orderly solid arrangement. - What is condensation?
Condensation is the conversion of vapor into liquid, opposite of evaporation. - What happens when a gas condenses?
Particles lose energy, move closer, and form a liquid. - What is the process of sublimation?
Sublimation is when a solid turns directly into gas without becoming liquid. - What happens to potential energy during sublimation?
Potential energy increases significantly, allowing particles to overcome solid structure forces. - What happens to kinetic and potential energy when temperature changes?
Kinetic and potential energy increase with rising temperature. Kinetic energy drops when temperature decreases. - What happens to potential energy during phase changes?
Only potential energy changes; temperature remains constant. - What is evaporation?
Evaporation occurs when surface molecules of a liquid gain enough energy to become vapor. - Where do molecules evaporate from?
From the surface of a liquid. - How does evaporation cool the surroundings?
High-energy molecules escape, lowering average energy and causing cooling. - Give examples of evaporation.
Drying clothes, water from lakes, sweat from skin. - What is boiling?
Boiling is when vapor forms throughout a liquid, not just the surface. - What forms during boiling?
Vapor bubbles that rise and burst, releasing gas. - At what temperature does water boil at sea level?
100°C (212°F). - Why does boiling need continuous heating?
To maintain temperature and sustain phase change. - How does external pressure affect boiling point?
Higher pressure raises, lower pressure reduces the boiling point. - What is the effect of lower pressure on evaporation?
Evaporation increases as molecules escape more easily. - What is the effect of lower pressure on boiling?
Liquids boil at lower temperatures under reduced pressure. - How does higher pressure affect evaporation?
Evaporation decreases as it becomes harder for molecules to escape. - How does higher pressure affect boiling?
Boiling point increases; more heat is needed. - Give an example of high-pressure effect in daily life.
Pressure cookers cook food faster due to higher boiling point. - What are the four variables that define the state of a gas?
Number of moles (n), volume (V), pressure (P), temperature (T). - What does Boyle’s Law state and how is it explained by kinetic theory?
Volume is inversely proportional to pressure. Less volume means more particle collisions, increasing pressure. - How does Charles’s Law describe the effect of temperature on gas volume?
Volume increases with temperature as particles move faster and occupy more space. - What does Avogadro’s Law tell us about gas volume and number of particles?
Volume is directly proportional to moles. More particles require more space to keep pressure constant. - What is diffusion and give a real-life example?
Movement from high to low concentration. E.g., perfume spreading in a room. - How does kinetic particle theory explain diffusion?
Particles move randomly and collide, mixing evenly until equilibrium. - How does Graham’s law relate molecular mass to diffusion rate?
Lighter molecules diffuse faster due to higher velocity at same kinetic energy. - How does temperature affect the rate of diffusion?
Higher temperature increases particle speed and diffusion rate. - Why does perfume feel cold when applied to the skin?
Evaporation absorbs heat from skin, causing a cooling sensation. - Why does sweating cool the body?
Sweat evaporates using body heat, lowering temperature. - What is sublimation and how is it explained by kinetic theory?
Direct change from solid to gas. Particles gain energy and escape the solid phase. - What types of substances undergo sublimation?
Dry ice, camphor, and naphthalene due to weak forces. - How is the speed of molecules related to temperature in sublimation?
Higher temperature increases speed and energy, enabling sublimation. - How is sublimation used in car and home air fresheners?
Solids transform to vapor, releasing fragrance. - What role does sublimation play in 3D printing?
Used in dye sublimation to embed ink into materials like T-shirts. - How is sublimation used in food preservation?
Freeze-drying removes moisture via sublimation, extending shelf life. - Give some examples of deposition in daily life.
Snow formation, soot deposits, dry ice from CO₂ gas. - Why is diffusion important in medicine?
Helps drugs move from application site to target tissues. - How does diffusion rate affect how quickly a drug works?
Faster diffusion leads to quicker therapeutic effect. - What factors affect the diffusion rate of drugs?
Concentration gradient, drug form, and release mechanism. - Why do liquid drugs diffuse faster than solid ones?
Liquid particles are already dispersed and move easily. - What is the purpose of controlled-release drug formulations?
They regulate drug diffusion for consistent, long-lasting effects.
Tags
Chemistry Grade 9
Diffusion
Federal Board
Gas Laws
Kinetic Particle Theory
Matter
Pakistan Curriculum
Phase Transition
Sublimation