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SCENARIO: You spilled cup of water in your room. You locked your room so that no one notices it. On your return, the water disappeared. What happened? Explain your thinking.

ANSWER: Evaporation is one of the two types of vaporization. The water that was spilled onto the floor had evaporated into the air. The water on the floor gained thermal energy, the atoms moved more vigorously, and phase changed to gas, or water vapor. The atoms practically gain sufficient energy to move apart and become a gas. Molecules in solids are closer together than molecules in liquids, and molecules in liquids are closer than molecules in gases. Also, evaporation can only happen when the air is not saturated with water.

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Scenario: Fuel line freeze-up or vapor lock. Vapor lock causes fuel to vaporize. Vapor will partially fill fuel line. This causes problems for  car's fuel pump.
In winter, water in gasoline tank can freeze and block the fuel line. Explain how temperature causes thee affects on the state of matter of the fuel.

The temperature outside needs to be really hot for the fuel to vaporize. The fuel turns from a liquid to a gas. Because the molecules in the air move a lot faster(which means they have more thermal energy), when the fuel sucks that energy, the molecules in the fuel start moving at the same speed as the speed of the molecules in the air, turning the fuel to vapor. Since the liquid turned into gas, that means that the intermolecular forces are weak.

The temperature outside needs to be really cold for the fuel to freeze. The fuel turns from a liquid to a solid. Since there is less thermal energy in the cold air, when the fuel takes in the cold air, it also becomes fuel with less thermal energy, which is what makes it a solid. Since the liquid turned into a solid, that means that the intermolecular forces are strong.

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Scenario: For your camping trip, you bought dry ice to keep food cold in an icebox. After 24 hours, dry ice disappeared. What happened to the dry ice? Explain why it was a better choice than regular ice and why not?
Answer: The dry ice sublimated and became C02 gas because it is absorbing heat from its surroundings, which in this case is the food. That is how the food stays cold. The dry ice was a better choice because it won't fill the icebox with water or get your food wet, and it's colder, since dry ice does not go through a liquid state. It's not better than regular ice because after it "melts", it stops cooling the food, on the other hand regular ice leaves behind a pool of cold water, because after the ice absorbs heat and melts, it becomes a liquid.

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Scenario: After your 5th period PE class on Friday, you were sweating. Explain why you were sweating and why it is important to sweat.
Explanation: Our theory is that when you get very hot, the thermal energy from the surroundings passes into the water in your sweat glands and makes it evaporate, which therefore cools you down. The intermolecular force caused by the heat when the sweat is on your skin becomes weaker and weaker, gradually evaporating the sweat and making the speed of the molecules faster and faster until the sweat evaporates. Sweating is extremely important because when it is hot outside, the sweat evaporates and makes your body cooler.

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Explain what might happen to a car that has only water instead of coolant(mixture of water and ethylene-glycol) in the radiator on very cold day? Also explain what happens on the hot day.

On a very cold day, I believe the water would freeze under the condition where the car is not running. Ethylene-glycol keeps coolant from freezing. The car would not be able to start. The molecules slow down so there is less heat and it will become a solid. As a solid, the molecules are closer together so the inter-molecular attraction is stronger.
On a hot day, I believe the car would overheat because the coolant keeps your car from overheating. But without ethylene-glycol, the water would evaporate very easily. With glycol, the coolant wouldn't evaporate easily because its boiling point is higher, so the engine isn't able to reach it. When there is ethylene-glycol with water when the water evaporates it takes more energy and heat with it. This makes the radiator cooler. The inter-molecular attraction is weaker in a gas form and as a liquid cooling the radiator the inter-molecular attraction is stronger which will cool down faster.

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Climber is moving up a waterfall in the Swiss Alps. In the winter the waterfall freezes. Why do ice and water have different properties even though they contain the same atoms and particles?

Ice and water have very different properties, because both are two different states of matter: solid and liquid. They become two different states of matter because the water has more energy, so its molecules move more due to the higher temperature and are more widely spaced, thus allowing the water to flow down the side of the mountain. In the winter however, the water loses thermal energy or heat to the surrounding air or objects, turning into ice. The ice has a lower temperature and has more densely packed molecules, making it solid. Water also has a weaker intermolecular force than ice, making it flow more easily, and since the molecules are further apart, it lets objects pass through it or flow with it, in the midst of the water itself. In ice however, the molecules are more densely packed, not allowing objects to pass through it.

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On ski trip, I noticed snow builds up in my patio, but after a few days it disappears. I did not notice any liquid water. What is going on??? Explain your thinking.

We had two theories. Our first one is that the snow melted into water, and the water built up into runoff, and streamed somewhere else, like into dirt.

Another theory is that the snow directly became water vapor. This is called sublimation and it is similar to when dry ice directly became gas. Sublimation is when a substance goes straight from the solid phase to the gas phase.When the temperature gets warmer and contrasts with the sudden cold, the snow takes the heat energy from the air and becomes gas!!!!!