Review Lecture Notes on Particle Theory

Kinetic energy What is an example in school of students having a lot of Kinetic energy and then less? When students go to Phys. Ed then go to a non-active lesson What is an example in school where students have no kinetic energy? English class Give an example in nature or daily life for each change: evaporation,, condensation and sublimation. Melting: when you get snow in your jacket, but when you go to take it off it’s just cold water Freezing: ponds freezing over in wintertime Evaporation: steam coming off of a hot pot Condensation: dew appearing on a blade of grass in the morning Sublimation: gas coming off of dry ice Heating curve of methanol the heating curve above, answer the following questions : 1. At what temperatures are the plateaux on the heating curve of methanol? 64°C and -97.7°C 2. What is the melting temperature of methanol ? -97.7°C 3. What is the boiling temperature of methanol? 64 °C 4. For each of the following temperatures, state if the methanol is a solid, a liquid, or a gas : ∙ at -120 oC : solid___ ∙ at -60 oC : liquid__ ∙ at 0 oC : ___liquid__ ∙ at 90 oC : _gas__ Heating curve of water Heating curve of water This graph is called a heating curve. It shows what happens to the temperature over time when a substance, starting as ice, is heated until it first melts then eventually boils. Interpret the heating curve above and answer the questions : The ice started at a temperature of 0° The heating was continued for 20_ minutes. The temperature (and state of matter)of water in relation to the time of it being heated was measured throughout the experiment The final temperature was : _125°_____ More Questions : 1. What was the temperature between 2 and 6 minutes? 0° 2. How come the temperature did not change during that time? Whenever something goes through a state change, the temperature stays the same for a while _________________________________________________________________________ 3. Between 6 and 10 minutes, was the water a solid, a liquid, or a gas? liquid 4. How do you know? I know that in between the first and the second plateau the matter is liquid __________________________________________________________________________ 5. What was the temperature between 10 and 18 minutes?_liquid 6. How come the temperature did not change during that time? Whenever something goes through a state change, the temperature stays the same for a while 7. What is a plateau on a graph? _a plateau is point that stays that way for a while Change of state and particle theory Particle theory continued What change of state is represented in this picture: Liquid to gas Describe what is happening to the particles in this change of state. The liquid particles started off as being generally close together, and did not move outside their container. However, when it turned into gas, the particles expanded and rose out of the jar in different directions. They also no longer have a fixed volume. What happens to the particles when a gas condenses to a liquid? The opposite of what just happened, the are confined to a container (and to gravity) and they become closer What happens to the particles when a liquid freezes into a solid? The particles come very close together and adapt a pretty neat position. They can barely move.