Question

HEAT

INTRODUCTION
Heat is a measure of the energy in a system. The transfer of energy is always from the system with more energy to the system with less energy. This lab has two distinct parts. In the first part, you will examine what happens to a gas when the temperature is changed. In the second part, you will use the idea of energy transfer to move water. You will need to be familiar with the ideas of phases (solid, liquid and gas), what specific heat is, and how to calculate joules. Please see pages 93-94, 99-101, and 106-110 in your textbook.
MATERIALS
1 small mouth (or small neck) bottle… a soda bottle should work
1 coin (dime or penny – must cover completely mouth of bottle)
1 large container to submerge at least ½ the bottle (sink, tub, bowl, etc.)
Enough cold water to submerge ½ the bottle
Measuring cups

Food coloring – in kit
4 cups water
1 large bowl to hold water – a clear glass one works best
1 small glass that will extend above water level when in bowl
Saran wrap/cling film – enough to cover bowl
1 small object (example: pebble, coin, marble)
Sunny days (3-4)




Lab 11 - Heat
Page 1 | 4







PART#1: Magic Coin?
Procedure:
Fill selected container with some cold water.
Place the bottle and coin in the bowl of water to chill them. The bottle must be submerged upside down. Submerge at least the neck of the bottle but if you have no “coin activity” on step four, repeat this step with either a greater amount of submersion or submerge the bottle for a greater amount of time.
Place the coin on the top of the bottle. There should be an airtight seal when you place the coin on the top of the bottle.
Wrap your hands around the bottle and wait for several seconds to a minute.
When you believe that the bottle is warmer than room temperature, allow the bottle to cool with the coin in place. Answer the following questions based on your observations.
Questions:
Approximately how long did you submerge the bottle in step #2?
What happened during step #4?
What happened during step #5?
Explain what is happening to the molecules to create the “coin activity”.

PART#2: Distillation
Procedure:
Add the water to the bowl.
Stir in the food coloring until it is distributed equally.
Place the empty glass (small) in the middle of the large bowl so that none of the


Lab 11 - Heat
Page 2 | 4







colored water can get into the glass. The glass must be short enough that it does not extend beyond the rim of the glass bowl.
Note: If the glass bowl is not working because the small empty glass is not stable, a stock pot/dutch oven (with a flat bottom) will work but it will need to be left alone for a little more time.
Cover the large bowl completely with the saran wrap so that no air can pass through.
Add the small object on the saran wrap so that the saran wrap dips in over the small empty glass but does not cause the saran wrap to slip off the lip of the bowl. Use a smaller pebble or coin if the first one is too heavy.
Leave the bowl in the sunlight for a few days and watch to see what happens.
Remove the small glass and measure the amount of water in it with the measuring cups (estimating to the nearest 1/8 cup). Contact me immediately if the amount of water in the small glass is less than 1/8 cup.
Questions:
How is the water in the large bowl different from the water in the small glass?
Describe step by step what happened to the water that is now in the small glass in terms of heating/cooling, phase changes, etc. (Hint: there is more than one step required)
How many cups of water (to the nearest 1/8 cup) are in the small glass?
How many grams of water did you collect?
The relationship between cups and grams is: 1 cup = 236 grams
How many calories are needed to heat the water?
Assume the following information:
The original temperature of the water in the large bowl was 25 °C.
The temperature of a molecule that changes from liquid to gas is 100 °C.
The specific heat of water is 1.00 cal/g·°C



Lab 11 - Heat
Page 3 | 4







You will need the equation for specific heat (equation 4.4)
How many calories are needed to evaporate the water?
The latent heat of vaporization of water is 540.0 cal/g
You will need equation 4.6 in the textbook.
How many calories (total) are needed to “move” the water from the large bowl to the small glass?

Notes: Ignore the amount of water that was not “moved” The water molecules must warm AND change state

Answer 1

I can provide an explanation of the principles involved in the lab, but I cannot perform the experiment or provide specific answers to the questions without access to the data.

In the first part of the lab, you will be exploring how the temperature affects the behavior of a gas in a bottle. The bottle and coin are chilled in cold water to reduce the pressure inside the bottle. When the coin is placed on top of the bottle, it forms an airtight seal. Then, when you wrap your hands around the bottle, the temperature of the air inside the bottle increases, causing the gas molecules to expand and increase the pressure inside the bottle. This pressure increase pushes the coin up slightly, creating the "coin activity" that you observe.

In the second part of the lab, you will be using the principles of energy transfer to move water from one container to another. By adding food coloring to the water, you can observe how the color stays in the large bowl while the water evaporates and condenses in the small glass. This process is known as distillation and involves heating the water until it changes state from a liquid to a gas, and then cooling it back down to a liquid. The saran wrap over the bowl helps to trap the water vapor and prevent it from escaping. The small object on top of the saran wrap creates a slight dip in the wrap, which allows the condensed water droplets to drip into the small glass.

To calculate the amount of energy needed to heat and evaporate the water, you will need to use the specific heat equation (q = m x c x ΔT) and the latent heat of vaporization equation (q = m x L). The specific heat equation calculates the amount of energy needed to raise the temperature of the water, while the latent heat of vaporization equation calculates the amount of energy needed to change the water from a liquid to a gas. Adding these two values together will give you the total amount of energy needed to "move" the water from the large bowl to the small glass.

Answer 2

Hello! This lab is all about heat, which is a measure of energy in a system. In the first part, we'll be examining what happens to a gas when the temperature changes. For this part, you will need a small mouth bottle, a coin, a large container, cold water, and measuring cups. In the second part, we'll be using the idea of energy transfer to move water. For this part, you will need food coloring, water, a large bowl, a small glass, cling film, a small object, and sunny days. Follow the procedures carefully and answer the questions provided to understand the concepts of heat and energy transfer. Don't hesitate to reach out if you have any questions!

C water = 1 cal/g ℃