Experiment With It Let’s investigate the emptiness of matter and the effect that adding thermal energy has on the force of attraction within liquids.
Objectives Students will be able to describe and model the empty spaces within and between molecules and atoms. Students will be able to explain the effect of adding thermal energy to liquids, and how the force of attraction is changed.
Hypothesis Using an “if…then…because…” format, record a hypothesis that describes the effects of adding thermal energy to a liquid.
Materials Part I - Teacher Demonstration
Part III - Water and Salt
Beads Marbles 2 250 mL Graduated cylinders Balance
1 100 mL Graduated cylinder 1 25 mL Graduated cylinder Container of sodium chloride Warm water (about 50ºC) Triple beam balance
Part II - Water and Ethyl Alcohol 2 250 mL Graduated cylinders Ethyl alcohol Warm water (about 50ºC) Triple beam balance or electronic balance
Part IV - Forces of Attraction in Liquids Waxed paper A few drops of water 2 Sealed test tubes of corn syrup Small container of ice Small container of warm water (about 50ºC) Eye dropper
Procedure Part I - Teacher Demonstration
The beads and marbles represent atoms in the demonstration. 1. Record the data given to you by your teacher on the data table.
Part II - Water and Ethyl Alcohol 1. Record the mass of one empty cylinder. Add 140 mL of ethyl alcohol and record the exact volume of the liquid and mass of the filled cylinder. 2. Record the mass of the second empty cylinder. Fill the cylinder with 60 mL of warm water and record the mass. 3. Pour the water into the cylinder of ethyl alcohol. Record the resulting volume of the liquid mixture and mass of the cylinder with both liquids. 4. Pour the mixture into the lab sink and rinse the cylinders.
Part III - Water and Salt 1. Record the mass of the 25 mL cylinder. Add salt to approximately the 10 mL mark and record the mass of both. 2. Record the mass of the 100 mL cylinder. Add 50 mL of warm water and record the mass. 3. Pour the salt into the cylinder of water. Gently swirl the mixture. Record the volume of the liquid mixture and mass of the cylinder with the mixture. 4. Pour the mixture into the sink and rinse and dry the cylinders.
Part IV - Forces of Attraction in Liquids 1. Place one sealed test tube of corn syrup into the container of ice. Place the other into warm water for about ten minutes. 2. Sprinkle drops of water on the sheet of waxed paper as it is held as flat as possible by two partners. Gently tilt the paper. Observe the force of attraction between the drops of water. 3. Remove the test tube of corn syrup from the container of ice. Turn the test tube upside down. 4. Observe the time it takes for the cold corn syrup to flow from one end of the test tube to the other. 5. Remove the test tube of corn syrup from the warm water. Turn the test tube upside down. Observe the time it takes for the warm corn syrup to flow from one end of the test tube to the other. ©2019 The NEED Project Thermodynamics
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