Chemical Reactions: How to Make a Salt
Questions: What are some common properties of salts? What is the difference between a chemical reaction and a physical reaction? How can we make a salt chemically?
Materials: 2 Ziploc bags with Calcium Chloride (CaCl2), 2 vials of 30mL Phenol Red (red water), 2 magnifiers, 4 thermometers, Tape, 2 vials of 20mL Baking Soda (NaHCO3), Clock, Paper and Pencil
Variables: Control:
Independent:
Dependent:
Procedures:
A.) You will be working in groups of two to three per table. (Materials per group).
B.) Follow ALL procedures on lab worksheet. Your teacher will guide you through each step of lab.
1.) Put 30 mL of phenol red water in vial. Carefully lift lid of “red water” vial and put thermometer in vial. What is the temperature of the water? ____________°C (THIS IS YOUR BEGINNING TEMPERATURE IN THE LAB!!!)
2.) Observe chemical compound CaCl2 in bag. Use magnifiers. Describe and name element parts:
3.) Put 20 mL of baking soda, NaHCO3, in a vial. Observe this chemical compound. Using magnifiers, describe and name its element parts:
4.) Add 15 mL (½) of colored water to the vial of baking soda (NaHCO3). Put the cap on this vial. What color is this mixture: _______________
5.) A.) Put (1) thermometer in bag with CaCl2 – make sure numbers are facing down on bottom of bag. Seal bag.
5.) B.) Tape your second thermometer to the outside of the Ziploc bag. The Thermometer should be placed near the bottom and on the side the bag. You will use BOTH thermometer readings to compare in this experiment (the thermometer inside the bag can be difficult to read in the second reaction).
6.) Look at chart on graph on back of lab worksheet to learn how to record temperature change. (Beginning temperature is the reading from step #1).
7.) Watch clock to time the reaction. Put 15mL (remaining ½) of red water in bag. Seal it. What is the color of the mixture of CaCl2 and ‘red’ phenol water: ____________________________________________.
8.) Check temperature every 30 seconds and record temperature on your chart.
9.) After 3 minutes, shake the capped vial of NaHCO3 with red water and pour contents quickly into the bag. SEAL THE BAG QUICKLY!
10.) Check temperature every 30 seconds and record temperature on your chart.
11.) Pour Ziploc contents into a jar with a coffee filtered jar near the sink to separate solids and liquids.
12.) Liquids in jar will be evaporated.
Results to be used for Discussion: You should answer the questions below and include them in your analysis when you discuss your findings. The answers to these questions these questions should also be incorporated into your conclusion when discussing what you learned.
A.) The solution will turn peach or orange if a salt was produced. Did your reaction produce a salt? _____________________________________________
B.) The coldest temperature was: ________°C The hottest temperature was: _________°C
C.) How do you know a gas was formed? _______________________________
D.) Which reaction gives off heat? ______________ + _____________________
E.) Name the chemical that makes the water get cold ______________________
F.) The chemical equation for this reaction is:
G.) Name the 2 reactants in this chemical reaction: _____________ & ________________
H.) Name the product that is a gas: ___________________________________
I.) Name the product that is a liquid: _________________________________
J.) Name the product that is a salt: ___________________________________
K.) Write the chemical formula for the product hydrochloric acid:________________________________________________________
L.) One of the products is chalk. Write the chemical formula for chalk: ____________________________________________________________
Graph Experiment Results: You will create a line graph. The horizontal or x-axis should be labeled as TIME, beginning with :30 seconds; the vertical or y-axis should be labeled as TEMPERATURE. If the temperature lowered below freezing in the second experiment, your graph should have NEGATIVE NUMBERS (this is dependent on your data). When you graph the first experiment, use one color and begin with your starting temperature and graph the temperatures that increased from the starting point. When you graph the second experiment, use a different color and start from your highest temperature and graph your results.