How Temperature Changes Impact Physical and Chemical Processes
Temperature is the measurement of heat of a system or substance. In most chemical reactions, the rate of an enzyme-catalysed reaction increases as the temperature is raised. Temperature is the internal energy contained within a particular system. Temperature can be measured by a thermometer. Celsius is the unit for measuring temperature, which is denoted by °C. Kelvin is also the unit of temperature. Temperature changes the states of matter into each other by decreasing or increasing. Temperature melts solid into a liquid state and this process is called melting or fusion.
Temperature Effect/Effect of Temperature
Temperature affects matter, reactions and enzymes in many different ways. The state of a substance can be changed by increasing or decreasing temperature. Solid can be converted to liquid on increasing temperatures and liquid can be converted to gas at high temperatures. Solid can be directly converted to gas at high temperatures. This process is called sublimation. Similarly, gases can be converted into liquids by decreasing temperature and increasing pressure and liquid can be converted into solids at low temperatures. Temperature also affects the rate of reaction in a positive or negative way.
The Effect of Change of Temperature on Solid State
The kinetic energy of the particles increases with increasing temperature. This increase in kinetic energy increases the speed of particles and the particles start vibrating with greater speed. The energy supplied by heat decreases or overcomes the forces of attraction between the particles. The particles remove from their fixed positions and start moving more freely. At a stage, the solid melts and is converted to liquid. The temperature at which solid melts to become a liquid is called its melting point. This process is called fusion when two separate solid objects made from the same substance are melted, they can get mixed together into a new one.
Effect of Change of Temperature on States of Matter
The main ways to change matter from one state to another are heating and cooling. We can convert a solid into a liquid by giving it heat. Similarly, liquid can be changed to gas by heating. The reverse is also true, when gas is removed, some of its heat energy becomes liquid. When a liquid is further removed, its heat energy becomes solid.
The kinetic energy of particles and inter-space between them increases due to the increasing temperature. This increase in kinetic energy and space between the particles decreases the force of attraction between particles.
Effect of Temperature on Pressure
Pressure is a physical force applied on an object by something in contact with it. Pressure is calculated as the force per unit area. The pressure exerted by the gas (which is enclosed in a chamber surrounded by a vacuum) on the walls of the chamber depends on three factors: the amount of gas in the chamber, the volume of the chamber and the temperature of the gas.
With respect to gases, the relationship between pressure and temperature is described. The pressure-temperature relationship is described by gas law which states that the pressure of a given amount of a particular gas is directly proportional to its temperature at a constant volume. It can be represented as:
\[P\alpha T\]
When the temperature of a particular system is increased, the speed of molecules in the gas becomes faster, exerting greater pressure on the wall of the gas container. Due to this, the pressure on the system increases. If the temperature of the system is decreased, the pressure also decreases. Therefore, the pressure of a particular gas is directly proportional to the temperature at constant volume.
When the temperature increases, the volume of the gas also increases at constant pressure. As the temperature increases, the kinetic energy of the molecule increases and the gas needs more volume to move that is why volume increases.
Examples of Effect of Temperature
One example of the effect of temperature on chemical reaction rates is the use of light sticks or glow sticks. The light stick undergoes a chemical reaction that is called chemiluminescence. But this reaction does not require or produce heat. Its rate is affected by temperature. Other examples are precipitation reaction, activation energy etc.
Interesting Facts
Solids can be converted into gases directly at high temperatures, which is called sublimation.
Temperature affects the reactivity of an enzyme catalyst.
The rate of reaction changes on decreasing or increasing temperature.
Key Features
Temperature can change the kinetic energy of particles of a substance. At high temperatures, the kinetic energy of particles is very fast and at low-temperature particles move slowly.
High temperature converts solids into liquids and liquids into gases.
Low temperature converts gases into liquids and liquids into solids.
Pressure is also increased with increasing temperature.
Summary
There is so much effect of temperature on the difference of the states of matter. The temperature affects different states of matter. As the temperature increases, the kinetic energy of the state increases but the force of attraction is different in every state. There is also an effect on the different states of matter at constant volume and constant pressure. As the volume is constant, the pressure of the gas decreases. When the pressure is constant, the volume of the gas increases.
FAQs on Effect of Change of Temperature Explained
1. What is the main effect of changing temperature on the particles of a substance?
When you increase the temperature of a substance, its particles gain energy and start moving faster. This increased kinetic energy causes the particles to vibrate more and move farther apart. Conversely, decreasing the temperature makes the particles lose energy, slow down, and move closer together.
2. How does an increase in temperature cause a solid to change into a liquid?
When a solid is heated, its particles gain enough kinetic energy to overcome the strong forces of attraction holding them in fixed positions. This process is called melting or fusion. The specific temperature at which a solid melts to become a liquid at atmospheric pressure is known as its melting point.
3. What happens to a liquid when its temperature is increased to its boiling point?
When a liquid reaches its boiling point, the particles have gained enough energy to overcome nearly all forces of attraction. They start to escape from the liquid to form a gas or vapour. This rapid, bulk process of a liquid changing into a gas is called boiling or vaporisation.
4. What is sublimation and can you give a common real-world example?
Sublimation is the special process where a solid changes directly into a gas without passing through the liquid state. A common example is camphor (kapur) or naphthalene balls, which you might see shrinking over time as they turn directly into a gas.
5. Why does the temperature of water stay at 100°C while it is boiling, even if we keep heating it?
This is because the extra heat energy being supplied is used to change the state of matter, not to raise the temperature. This hidden energy, called the latent heat of vaporisation, is used to break the bonds between water molecules so they can escape as steam. The temperature only starts to rise again once all the water has turned into steam.
6. What is the main difference between boiling and evaporation?
While both processes turn a liquid into a gas, they are different in key ways:
- Temperature: Boiling happens at a specific temperature (the boiling point), while evaporation can happen at any temperature below the boiling point.
- Location: Boiling is a bulk phenomenon that happens throughout the entire liquid, which is why you see bubbles forming. Evaporation is a surface phenomenon, where only particles at the surface escape.
- Speed: Boiling is a fast and energetic process, while evaporation is a slow and silent one.
7. How does the concept of evaporation explain why we feel cool after sweating?
When we sweat, the water (sweat) on our skin needs energy to turn into vapour. It takes this heat energy from our body. As the sweat evaporates, it removes heat from our skin, which makes us feel cool and refreshed. This is a practical example of cooling caused by evaporation.
8. Can temperature change affect a substance without changing its state (solid, liquid, gas)?
Yes. Besides changing states, temperature changes can cause thermal expansion and contraction. Most materials expand (get slightly larger) when they are heated and contract (get slightly smaller) when they are cooled, even without changing their state. This is why small gaps are left in railway tracks and bridges.
