Questions and Answers
Which of the following are matter? (Select all that apply)
What happens to the salt when it is dissolved in water?
It spreads throughout the water.
What is the opinion of the first school of thought about the nature of matter?
They believed that matter is continuous like a block of wood.
What characteristic of matter does a diver cutting through water demonstrate?
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What are the two states of matter that can diffuse into liquids?
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What is the effect of temperature change on the particles of matter?
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Particles of matter attract each other.
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What is the latent heat of fusion?
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Which state of matter fills the entire volume of its container?
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What happens when pressure is applied to a gas?
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What is sublimation?
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Gases are less compressible than liquids.
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The unit of pressure is ______.
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What is the atmospheric pressure at sea level?
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What is the physical state of water at 250°C?
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What is the physical state of water at 100°C?
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Why does the temperature remain constant during a change of state?
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Name one factor that increases the rate of evaporation.
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Can you suggest a method to liquefy atmospheric gases?
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What happens to water when it is left uncovered?
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Why do we see water droplets on the outer surface of a glass containing ice-cold water?
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What type of clothes should we wear in summer?
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How does the water kept in an earthen pot become cool during summer?
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Evaporation occurs at all temperatures.
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Why is ice at 273 K more effective in cooling than water at the same temperature?
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What produces more severe burns, boiling water or steam?
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Match the following states of matter with their characteristics:
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What happens to particles of matter at a given temperature?
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What is sublimation?
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What is deposition?
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Study Notes
Matter in Our Surroundings
- Matter encompasses everything around us, including air, food, stones, clouds, stars, and living organisms, characterized by having mass and volume.
- Historical classifications of matter include the early Indian concept of "Panch Tatva" and Greek philosophies, both identifying fundamental elements.
- Modern science classifies matter based on physical properties and chemical nature.
Physical Nature of Matter
- Matter consists of particles which can either be continuous or particulate in nature.
- Activities demonstrate how dissolving substances like salt or potassium permanganate in water shows the dispersion of particles, indicating matter's particulate nature.
Characteristics of Particles of Matter
- Particles of matter possess space between them, allowing them to intermingle and diffuse into one another.
- Particles are in constant motion and the kinetic energy of these particles increases with temperature.
- Diffusion is influenced by temperature, indicating that heat accelerates particle movement and mixing capabilities.
- Particles attract each other, with the strength of attraction varying among different types of matter.
States of Matter
- Matter exists in three states: solid, liquid, and gas. Each state exhibits unique properties due to variations in particle arrangement and movement.
The Solid State
- Solids have a definite shape, fixed volume, and distinct boundaries. They are rigid and maintain their shape when a force is applied.
- Compression of solids is possible but difficult, while they break under excessive force.
- Examples include common objects like books and pens.
The Liquid State
- Liquids possess a fixed volume but take the shape of their container, demonstrating fluidity.
- They flow easily and have negligible compressibility compared to solids.
- Diffusion occurs in liquids, allowing for seamless mixing of different liquid types.
The Gaseous State
- Gases are highly compressible and can occupy a large volume in a small container.
- The particles in gases move randomly at high speeds, facilitating rapid diffusion and mixing with other gases.
- Observations reveal that gases can spread rapidly, such as the aroma from cooked food reaching people quickly.
Conclusion
- Understanding the properties and behaviors of matter in different states is fundamental to studying physical science and its application in real-world phenomena.### Density of Substances
- Density is defined as mass per unit volume (Density = mass/volume).
- In order of increasing density: air < exhaust from chimneys < cotton < chalk < water < honey < iron.
Characteristics of States of Matter
- Solid: Rigid, not compressible, maintains shape, low kinetic energy.
- Liquid: Less rigid, moderately compressible, takes the shape of the container, intermediate kinetic energy.
- Gas: No rigidity, highly compressible, fills the container, high kinetic energy.
Gas Behavior
- Gases completely fill their containers due to high kinetic energy and minimal intermolecular forces.
- Gases exert pressure on container walls because of particle collisions.
Density Anomalies
- Ice floats on water despite having lower density than water; this is due to the unique structure of ice's molecular arrangement.
States of Matter Changing
- Water exists in three states: solid (ice), liquid (water), gas (water vapor).
- During state changes, the arrangement and energy of particles change due to temperature.
Heating Ice Experiment
- Heating ice leads to its melting; temperature remains constant during phase changes until fully transformed.
- Latent heat is the hidden energy absorbed during state changes, such as fusion (solid to liquid) and vaporization (liquid to gas).
- Melting point of ice: 273.15 K; boiling point of water: 373 K.
Sublimation and Deposition
- Sublimation is the direct change from solid to gas (e.g., dry ice), while deposition is gas to solid.
Effects of Temperature and Pressure
- Increasing temperature raises kinetic energy, allowing particles to overcome forces of attraction, leading to phase transitions.
- Increasing pressure on gases can lead to a liquid state, as particles are forced closer together.
Factors Affecting Evaporation
- Evaporation is a surface phenomenon where only the liquid's surface particles escape into vapor.
- Factors increasing evaporation include:
- Increased surface area (e.g., spreading wet clothes)
- Higher temperature (more particles gain energy)
- Lower humidity (less water vapor in the air)
- Increased wind speed (moving vapor away from the surface).
Cooling through Evaporation
- Evaporation causes cooling as particles absorb heat from the surroundings during the state change.
- Example: Sprinkling water on a hot surface cools it down.
Real-Life Applications of Evaporation
- Cotton clothes help regulate body temperature in summer by encouraging sweat evaporation.
- Acetone on skin feels cool due to evaporation absorbing body heat.
Summary of Matter
- Matter comprises small particles in three states: solid, liquid, and gas.
- States vary in terms of attractive forces: strongest in solids, moderate in liquids, weakest in gases.
- The arrangement of particles is most ordered in solids and chaotic in gases.
- States are inter-convertible via changes in temperature and pressure, along with phenomena like sublimation and deposition.
- The rate of evaporation depends on multiple factors—surface area, temperature, humidity, and wind speed.### Latent Heat of Fusion
- Latent heat of fusion refers to the heat energy needed to convert 1 kg of solid into liquid at its melting point.
Measurable Quantities and Units
- Temperature is measured in kelvins (K).
- Length is measured in metres (m).
- Mass is quantified in kilograms (kg).
- Weight is expressed in newtons (N).
- Volume is represented in cubic metres (m³).
- Density is defined as kilograms per cubic metre (kg m⁻³).
- Pressure is measured in pascals (Pa).
Temperature Conversions
- Convert 293 K to Celsius.
- Convert 470 K to Celsius.
- Convert 25°C to Kelvin.
- Convert 373°C to Kelvin.
Observations and Explanations
- Naphthalene balls gradually disappear without leaving solid residue due to sublimation.
- The scent of perfume can be detected from several metres away due to diffusion.
Forces of Attraction in Substances
- Arrange water, sugar, and oxygen in order of increasing forces of attraction between particles.
Physical States of Water
- Water is liquid at 25°C.
- Water is solid (ice) at 0°C.
- Water is in gas form (steam) at 100°C.
Justifications for States of Matter
- Water at room temperature is liquid due to molecular motion and thermal energy.
- An iron almirah remains solid at room temperature due to strong intermolecular forces.
Cooling Effectiveness
- Ice at 273 K is more effective in cooling than water at the same temperature due to its latent heat absorption during melting.
Severity of Burns
- Steam produces more severe burns than boiling water due to its higher energy content.
Diagram Labels for Change in State
- Identify and label points A, B, C, D, E, and F in the change of state diagram.
Group Activity: Particle Movement Model
- Create a model demonstrating particle movement in solids, liquids, and gases using a transparent jar, rubber balloon, string, and seeds such as chickpeas or dry peas.
- The model can illustrate the states of matter by varying the tension and movement on the string to mimic particle dynamics.
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Description
This quiz covers the basics of matter, its properties, and its presence in our surroundings. It includes concepts related to shapes, sizes, and textures of various objects.
