15 Questions
Why does the temperature remain constant during the change of state for any substance?
Because the energy supplied is used to overcome the forces of attraction between particles, rather than increase kinetic energy.
Suggest a method to liquefy atmospheric gases.
By compressing the gas at low temperatures.
Give examples from everyday life where change of state from liquid to vapor takes place without reaching the boiling point.
Water evaporating slowly when left uncovered, and wet clothes drying up.
Define sublimation.
A change of state directly from solid to gas without changing into liquid state.
What is deposition?
The direct change of gas to solid without changing into liquid.
Explain how liquefaction of gases can be achieved.
By applying pressure and reducing temperature, gases can be liquefied.
What is solid carbon dioxide also known as?
Solid carbon dioxide is also known as dry ice.
Describe the conversion process of solid carbon dioxide into gaseous state.
Solid carbon dioxide gets converted directly into the gaseous state on decreasing pressure to 1 atmosphere without becoming a liquid.
How do pressure and temperature determine the state of a substance?
Pressure and temperature determine whether a substance will be solid, liquid, or gas.
Explain the concept of sublimation with an example.
Sublimation is the process in which a substance changes directly from a solid to a gas without passing through the liquid state. An example of sublimation is solid carbon dioxide (dry ice) turning into carbon dioxide gas.
Describe the process of deposition and provide an example.
Deposition is the process in which a substance changes directly from a gas to a solid without passing through the liquid state. An example of deposition is frost forming on a cold surface.
Explain the liquefaction of gases and why it is important.
Liquefaction of gases is the process of converting a gas into a liquid state by cooling or increasing pressure. It is important because liquefied gases take up less space, making them easier to transport and store.
How does pressure affect the states of matter?
Pressure can affect the state of matter by compressing gases into liquids or solids. Increasing pressure can lead to liquefaction of gases and changes in the physical state of matter.
Explain the concept of solid carbon dioxide and its properties.
Solid carbon dioxide, also known as dry ice, is a substance that sublimes directly from solid to gas. It is extremely cold and is often used for cooling purposes.
What are the effects of sublimation on the environment?
Sublimation can contribute to the water cycle by allowing substances like ice to turn into water vapour without melting into liquid water. It also plays a role in the formation of frost and snow.
Study Notes
Change of State
- Temperature remains constant during the change of state for any substance because the energy absorbed or released is used to change the state, not to change the temperature.
Liquefaction of Gases
- Liquefaction of gases can be achieved by applying high pressure and low temperature.
- Example: Liquefaction of oxygen and nitrogen from atmospheric air to produce liquid oxygen and liquid nitrogen.
Change of State Examples
- Examples of change of state from liquid to vapor without reaching the boiling point include:
- Evaporation of water from the skin while sweating
- Evaporation of petrol from the surface of a car
Sublimation
- Sublimation is the transition of a substance from the solid to the gas phase without going through the liquid phase.
- Example: Iodine crystals subliming into a purple vapor.
Deposition
- Deposition is the transition of a substance from the gas to the solid phase without going through the liquid phase.
- Example: Water vapor in the air freezing into frost on a cold windowpane.
Liquefaction of Gases Importance
- Liquefaction of gases is important for various industrial applications, including the production of liquefied petroleum gas (LPG) and liquefied natural gas (LNG).
Solid Carbon Dioxide
- Solid carbon dioxide is also known as dry ice.
- Conversion process of solid carbon dioxide into gaseous state: solid CO2 (dry ice) → gaseous CO2
Pressure and Temperature
- Pressure and temperature determine the state of a substance, with high pressure and low temperature favoring the solid or liquid state, and low pressure and high temperature favoring the gas state.
Sublimation Effects
- Sublimation can have environmental effects, such as the loss of water from crops and soil due to rapid sublimation of frost.
Pressure Effects
- Pressure affects the states of matter by influencing the arrangement of particles, with high pressure favoring closer packing and lower pressure favoring greater spacing.
Dry Ice Properties
- Solid carbon dioxide (dry ice) has the following properties:
- Sublimes directly into carbon dioxide gas
- Very cold, with a temperature of -78.5°C
- Used as a coolant and for preserving food
Test your knowledge on sublimation and deposition by inferring the process from a given activity. Learn about the direct change of state from solid to gas and gas to solid without passing through the liquid state.
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