Purpose: The purpose of this demonstration is to determine the effect different salts have on the temperature of water and to read and interpret chemical reactions.
Salt 1: Potassium Chloride (KCl):
Step 1: Record the initial temperature of the water below.
Temperature of water: ______________
Step 2: Observe as your teacher adds ~5 grams of potassium chloride to the beaker of water.
Step 3: Have the class time keeper begin the timer for 3 minutes.
Write down one observation.
Step 4: Record the temperature of the solution.
Temperature of water + salt after 3 minutes: _____________
Step 5: Interpret the chemical reaction for the formation of potassium chloride:
KCl + H2O → HCl + KOH
Reactants
How many H atoms?
How many Cl atoms?
How many O atoms?
How many K atoms?
Products
How many H atoms?
How many Cl atoms?
How many O atoms?
How many K atoms?
Salt 2: Calcium Chloride (CaCl2)
Step 1: Record the initial temperature of the water below.
Temperature of water: ______________
Step 2: Observe as your teacher adds ~5 grams of calcium chloride to the beaker of water.
Step 3: Have the class time keeper begin the timer for 3 minutes.
Write down one observation.
Step 4: Record the temperature of the solution.
Temperature of water + salt after 3 minutes: _____________
Step 5: Interpret the chemical reaction for the formation of calcium chloride and water:
CaCl2 + H2O → 2HCl + CaO
Reactants
How many H atoms?
How many Cl atoms?
How many O atoms?
How many Ca atoms?
Products
How many H atoms?
How many Cl atoms?
How many O atoms?
How many Ca atoms?
Salt 3: Ammonium Chloride (NH4Cl)
Step 1: Record the initial temperature of the water below.
Temperature of water: ______________
Step 2: Observe as your teacher adds ~5 grams of calcium chloride to the beaker of water.
Step 3: Have the class time keeper begin the timer for 3 minutes.
Step 4: Record the temperature of the solution.
Write down one observation.
Temperature of water + salt after 3 minutes: _____________
Step 5: Interpret the chemical reaction:
NH4Cl + H2O → NH4,+ + Cl- + H2O
Reactants
How many H atoms?
How many Cl atoms?
How many O atoms?
How many N atoms?
Products
How many H atoms?
How many Cl atoms?
How many O atoms?
How many N atoms?
Analysis Questions:
What observations suggest that a chemical change occurred when the salts dissolved?
In this experiment, we added about 5 grams of salt to the water. What do you think would happen if we added 20 grams of salt instead?
Which salt would you use to design a new hot pack that can be used to relieve pain? Use evidence from the experiment to support your answer.
The Johnson & Johnson COVID-19 vaccine has several advantages that will allow it to be applied across many low and middle-income countries. It is a single dose and remains stable for months with normal refrigeration. However if electricity for refrigeration is not available or if power fails all of the vaccine will be lost. Which salt would you use to design a backup refrigeration system that can be used to cool down the vaccines in case of power outages? Use evidence from the experiment to support your answer.
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Purpose: The purpose of this demonstration is to determine the effect different salts have on the temperature of water and to read and interpret chemical reactions.
Salt 1: Potassium Chloride (KCl):
Step 1: Record the initial temperature of the water below.
Temperature of water: ______________
Step 2: Observe as your teacher adds ~5 grams of potassium chloride to the beaker of water.
Step 3: Have the class time keeper begin the timer for 3 minutes.
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