Heat and matter
[1] Respond to the following statement: “Heat and temperature are the same thing; heat is the energy added or removed and the temeprature is a measure of the heat.” Is the statement satisfactory under all circumstances you can think of?
Consider: Heating two containers of water, one with twice as much water.
Heating equal mass samples of two different materials.
Heating 200g of ice at 0 ºC.
[2] Most materials expand when heated. This is best explained by a) the molecules expanding. c) air in the material expanding.
Explain your reasoning using evidence. b) increased motion of the molecules. d) space needed for the added heat.
[3] Solid Osmium is the most dense of the elements. This is explained by a) The mass of the atoms packed together. b) The smallerspace between the atoms. c) The number of atoms per cubic centimeter.
Explain your answer considering:
Densities of lead, uranium, and other solid elements (link: http://www.standnes.no/chemix/periodictable/density-chart-elements.htm
)
[4] Consider the following samples of matter: ice, liquid water, water vapor, solid copper, frozen methane (CH
4
), salt (NaCl) and diamond. Describe the structure of each of these in terms of particles (atoms or molecules), including spacing and what holds the structures together. Also describe how the structure accounts for such things as hardness, melting point and rigidity or malleability. Iclude sketches of the particles in a sample of water in the solid, liquid and gaseous states.
Consider: Oscillators
Forces
[5] When water boils or dry ice (solid CO
2
) sublimates to gas, what happens to the molecules in the liquid as they enter the gas phase?
[6] A glass of water sitting on a counter is at a fixed temperature of 24 ºC throughout. Describe the motion of the water molecules in the glass. If the average speed of water molecules at this temperature is 50 m/s, describe how the speed of the particles in the glass of water compare to this.
Consider: evaporation of water at this temperature.
The average speed of molecules in water vapor at 24 ºC is 523 m/s
[7] Describe the process of evaporation at temperatures below the boiling point.
[8] Describe the plot of temperature versus time when heating 100g of ice at -10 ºC to vapor at
150 ºC. Assume the rate of heat addition to be constant and account for the rate of change of temperature for each portion of the graph with a different slope.

[9] A copper rod is heated to 100 ºC at one end and cooled to 10ºC at the other. Describe the temperature along the rod, what the particles in the rod are doing and what is going on with heat in the rod.
Consider: How do you keep the temperatures at the ends constant?
What happens after a long time, given your explanation?
[10] A copper block at 80 ºC is placed in a beaker of water at 10ºC. Describe what happens with the heat, copper particles and water particles over time. How does the temperature of the copper compare to the temperature of water an hour later?
Consider: Your lab results.
[11] How does the Sun heat the Earth? Remember there is a vacuum between them.
[12] You have been visiting Las Vegas and parked the car in an open parking lot for the day.
Unfortunately, it is September and the interior is extremely hot. Assuming everything inside the car is at thermal equilibrium, what can you touch without extreme discomfort and what is it about those objects which accounts for this?
[13] Evaluate the statement “When you heat an object, the particles move faster. The increased friction between the particles is what warms the object.”
Consider: What caused the increased motion prior to the friction?
What is friction at the atomic level?
[14] Evaluate the statement “A leak-free contaier of hot water will freeze faster than an identical container of cold water.”
Consider: Colling rate and temperature.
Temperature of the hot water after it has cooled for a while.