Lesson 6 - Physical Change PDF

Physical change To change one or more physical properties in which the matter’s identity stays the same Decide Which of the following is not physical change? Water turns into ice Baking cake Frying an egg Burning a match Cutting a paper Folding clothes Rusting of iron Water droplets o...

Physical change To change one or more physical properties in which the matter’s identity stays the same Decide Which of the following is not physical change? Water turns into ice Baking cake Frying an egg Burning a match Cutting a paper Folding clothes Rusting of iron Water droplets on the lid of a cooking pan A green tomato turns red when it ripens  What is involved to getting matter to change state? Transferring energy to or from a substance can change its state. A form of energy is Thermal energy. How can state of matter be changed? melting Evaporation Condensation Freezing Change from solid to gas (p:250) Sublimation  The change of state from solid to liquid Melting The change of state from liquid to solid The change of state from liquid to gas Freezing The change of state from gas to liquid The change in a substance that can be changed back again Evaporation condensation Reversible change Watch the video then answer the following questions: (10 mins) Q1: Does The number of particles change during a change of state? Q2: Does The total mass of the matter change during a change of state?  Does The number of particles change during a change of state? No, only their spacing and arrangement changes. Does The total mass of the matter change during a change of state? The total mass has not changed. It does not matter if a substance melts, freezes, boils, evaporates, condenses or sublimates - the mass does not change. These changes in state are called physical changes because the process can be reversed.  What happens to the particles in the ice cube to cause a change in state? Melting Matter can change state when it gains or loses enough thermal energy. When the temperature of a substance increases, the particles speed up. when particles speed up, they break away from the other particles. This is the melting point of a substance. Vaporization: The change in state from a liquid to a gas is vaporization. Vaporization that occurs throughout a liquid is called boiling. The boiling point: The temperature needed for a substance to boil. A substance's temperature will remain at its boiling point until all of the particles have changed from liquid to gas. The bubbles contain water vapor, a gas Evaporation: is vaporization that occurs only at the surface of a liquid. When the particles at the surface of the puddle gained enough energy from the Sun to overcome the attractive forces holding them to the rest of the particles in the puddle, they broke away as gas. Pressure and Evaporation: Not only do the particles need to overcome the attractive forces between the particles, they must also overcome the force of air pressure. For a particle to evaporate, it must overcome the force of air pressure to escape from the surface of the liquid.  What is the opposite processes of melting and evaporating and give examples Freezing: The opposite of melting is freezing, the change of state from a liquid to a solid. The freezing point: is the temperature at which a liquid changes to a solid. Freezing requires the removal of thermal energy. As energy is removed from liquid particles, they slow down and have less energy to overcome the attractive forces between particles and will start to form an organized structure. Condensation: The removal of thermal energy from a gas, and a liquid is formed. Condensation is similar to freezing. As energy is removed, the particles in the gas move slower and cannot overcome the attractions between each particle and the liquid condenses. Channels analyze figure 11 Time