NTHS Chemistry Labs Quarter 3 Percent Water in a Hydrate Pre-Lab

NTHS Chemistry Labs Quarter 3 Percent Water in a Hydrate

Pre-Lab & Procedure

Name: ______Date: ______

Chemistry Lab Mr. Zamojski Q3 – Percent Water in a Hydrate PRE-LAB ASSIGNMENT

Required Safety Data Sheets (SDS): 1) Copper (II) Sulfate, Pentahydrate 2) Copper (II) Sulfate, Anhydrous

Required Pre-Lab Video: ZamJ713 channel on YouTube: “Quarter 3 Chemistry Lab – Percent Water in a Hydrate”

QUESTIONS: Refer to the information from the pre-lab video to answer the questions below.

1) The process you will execute in this lab is similar to ______, which a separation process that exploits differences in ______between substances.

Hydrates

2) A hydrate is an ______compound that has ______as part of its crystal structure.

3) Is a molecule of water SYMMETRICAL or ASYMMETRICAL? ______

4) Is a molecule of water NONPOLAR or POLAR? ______

5) Label the + (positive) and – (negative) sides of the water molecule. Then indicate whether each circle next to the water molecule represents a + (positive) ion or a – (negative) ion.

6) A ______is a continuous array of ______and ______ions

7) In a hydrate the water molecules are ______within the ionic lattice due to strong electrostatic ______.

8) To remove water from a hydrate, temperatures higher than the ______of water are needed.

9) An ______compound has all the ______removed from its ionic lattice.

Lab Equipment

10) What are the three materials that will be used for heating?

i) ______

ii) ______

iii) ______

11) What is the name of the porcelain bowl you will use that is designed to withstand high temperatures?

______

12) What is the name of the triangular holder for your porcelain bowl? ______

Lab Safety

Refer to the SDS for Copper(II) Sulfate, Pentahydrate.

7) Refer to Section 2 – Hazards Identification.

a) This chemical is ______if swallowed. Do not ______, ______, or smoke

when using this product.

b) This chemical causes ______and serious ______irritation.

8) Refer to Section 9 – Physical and Chemical Properties

a) What color is this chemical? ______

9) Refer to Section 11 – Toxicological Information

a) What are the acute effects of exposure to this chemical?

i) ______

ii) ______

iii) ______

Refer to the SDS for Copper(II) Sulfate, Anhydrous.

10) Refer to Section 2 – Hazards Identification.

a) This chemical is ______if swallowed. Do not ______, ______, or smoke

when using this product.

b) This chemical causes ______and serious ______irritation.

11) Refer to Section 9 – Physical and Chemical Properties

a) What color is this chemical? ______

12) Refer to Section 11 – Toxicological Information

a) What are the acute effects of exposure to this chemical?

i) ______

ii) ______

iii) ______

13) What will you wear throughout this laboratory activity to protect yourself from these chemical hazards?

______AND ______

14) The goal of this lab is to find the mass of ______in the hydrate.

Doing the Lab

15) For your first procedure step you will measure the mass of an ______.

16) Next you will measure out ______to ______grams of copper(II) sulfate, pentahydrate.

Heating the Sample

17) What two precautions should you take before lighting the Bunsen burner?

i) ______

ii) ______

18) Next you will first place your ______on the iron ring and then place your ______on top of that.

a) Make sure that your pipeclay triangle is ______enough to prevent the crucible from

______

19) What is the proper order for lighting a Bunsen burner? ______FIRST

THEN ______

a) After lighting your Bunsen burner make sure you have a ______,

______flame

b) If you need to adjust the height of iron ring,

I) FIRST ______

II) THEN ______

20) Now you should wait and safely ______the sample while it is heating.

21) Next place the crucible cover on the crucible using ______.

22) Next transfer the crucible and cover to a ______using ______.

After Cooling

23) Now measure the mass of your ______and ______sample.

24) For your last step you will add ______to the ______sample in the crucible.

Mass Calculations

25) How will you calculate the mass of the anhydrous sample?

Mass of Anhydrous Sample = ______–______

26) How will you calculate the mass of water in the original sample?

Mass of Water = ______–______

Name: ______Date: ______

Partner(s): ______

Chemistry Lab Mr. Zamojski Q3 – Percent Water in a Hydrate LAB PROCEDURE

Purpose: The purpose of this activity is to observe and measure the changes in the hydrated ionic compound copper(II) sulfate, pentahydrate (CuSO4•5H2O) as it changes from hydrous to anhydrous and to determine the percent composition of water in the hydrated ionic compound.

LAB GRADE Your grade for this lab will be based on the following criteria: • Using the proper safety equipment (goggles & disposable gloves) • Following procedures and staying on task at your lab station • Following safe practices and properly handling accidents • Cleaning up your lab station • Completing the lab report

Materials: goggles Bunsen burner tongs disposable gloves ring stand scoopula iron ring crucible & cover copper(II) sulfate, pentahydrate (CuSO4•5H2O) lighter pipette digital scale wire mesh pipeclay triangle water tongs

** Handle the crucible and cover with great care. They have a high tolerance for heat, but they are very BRITTLE and will crack easily**

Procedure: 1) Put on goggles and disposable gloves. 2) Place the crucible on the digital scale and record its mass in the DATA TABLE. 3) Press the TARE or ZERO button. The digital reading should now indicate “0.0 g”. 4) Using a scoopula carefully add between 3.0 g and 4.0 g of CuSO4•5H2O to the crucible. Record the mass in the DATA TABLE.

5) Record any observations you make about the CuSO4•5H2O in the DATA TABLE. 6) Set up your ring stand, iron ring, and Bunsen burner. Lock in the metal ring so that it is about 10. cm above the top of your Bunsen burner.

7) Place the pipeclay triangle on the iron ring. Then place your crucible with CuSO4•5H2O on the pipeclay triangle. 8) Light your Bunsen burner by igniting your lighter or match FIRST and then turning on the gas. a. Make sure that you have a blue, non-luminous flame before continuing.

9) Adjust the height of your iron ring, so that the tip of the inner blue flame it just below the crucible. Then slide your Bunser burner under the crucible. 10) Heat the contents of the crucible. Record any observations you make in the DATA TABLE. a. Do NOT look directly into the crucible. 11) Once your sample in the crucible has completely changed color, then place the crucible cover on top of the crucible using tongs and wait for 2 more minutes. 12) After 2 minutes have passed, turn off your Bunsen burner. 13) Using tongs place the cover and the crucible on top of a wire mesh. Wait for 5 minutes for the crucible to cool. Make observations about the sample in the DATA TABLE 14) After 5 minutes using tongs transfer the crucible to the digital scale. Record the mass of the crucible and sample in the DATA TABLE. 15) Using tongs place the crucible on the lab table. 16) Using a pipette drip water into the sample inside the crucible. Record your observations in the DATA TABLE.

Clean Up: a. Do not touch anything hot with your hands. Leave all hot materials out to cool. b. Return all materials you used to their original location in the lab. c. Clean off your lab station using a sponge, soap, and water. Dry your lab station with paper towels. d. Wash your hands with soap and water.

DATA TABLE: Observations Original Sample

During Heating

After Heating

After Adding Water

Measurements Mass of empty crucible

Mass of hydrous copper (II) sulfate

Mass of crucible & anhydrous copper (II) sulfate

Calculate the Mass of anhydrous copper (II) sulfate

Calculate the Mass of Water Removed

Chemistry Laboratory Write-up Checklist

Your lab write-up is due by FRIDAY, APRIL 13, 2018.

Experiment: Percent Water in a Hydrate Name ______

Safety, 1. Used goggles Procedures, 2. Followed procedures and stayed on task

& Cleanup 3. Followed safe practices (5 points) 4. Cleaned up lab station prior to leaving Purpose and

Design 1. What were you trying to learn in this lab? 2. Briefly describe the procedure you used. (2 points) Include the following: Data & 1. Completed DATA TABLE

Evaluation

(9 points)

Conclusions 1. Explanation of color changes (9 points) 2. Calculation of actual percent water 3. Calculation of measured percent water 4. Percent Error calculation 5. Evaluation of percent error

Maximum Score = 25 points Your score: ______

Name: ______Lab: Percent Water in Hydrate

PURPOSE: In the lab I heated a sample of ______(______)______, penta______to change it from ______to ______by driving out the

______stuck in the compound’s ionic lattice. Then I measured the difference in mass between the ______and ______compound to determine the percent composition of ______in the hydrated ionic compound.

EXPERIMENTAL DESIGN: In this experiment I measured the mass of a sample of ______.

Then I heated this sample using a ______in a porcelain container called a ______until the sample’s color changed from ______to ______.

Then I measured the mass of the sample after heating using a ______.

DATA & EVALUATION:

** Attach your DATA TABLE.

CONCLUSIONS:

1) What happened to the color of the sample when it was heated? Explain why this happened.

2) What happened to the color of the sample when you added water? Explain why this happened.

3) Calculate the actual percent composition of water (H2O) in copper (II) sulfate pentahydrate (CuSO4•5H2O).

푀표푙푎푟 푀푎푠푠 표푓 푊푎푡푒푟 × 5 퐴푐푡푢푎푙 푃푒푟푐푒푛푡 푊푎푡푒푟 = × 100% 푀표푙푎푟 푀푎푠푠 표푓 퐶표푝푝푒푟 (퐼퐼) 푆푢푙푓푎푡푒 푃푒푛푡푎ℎ푦푑푟푎푡푒

4) Using the measurements from your DATA TABLE calculate the measured percent composition of water in the hydrate. 푀푎푠푠 표푓 푊푎푡푒푟 푅푒푚표푣푒푑 푀푒푎푠푢푟푒푑 푃푒푟푐푒푛푡 푊푎푡푒푟 = × 100% 푀푎푠푠 표푓 퐻푦푑푟표푢푠 퐶표푝푝푒푟(퐼퐼) 푆푢푙푓푎푡푒

5) Percent Error is a calculation used to determine how accurate the results of your experiment are by comparing the measurements or values you obtained to the accepted measurement or value. The following equation is used. 퐶푎푙푐푢푙푎푡푒푑 푉푎푙푢푒 − 퐴푐푐푒푝푡푒푑 푉푎푙푢푒 푃푒푟푐푒푛푡 퐸푟푟표푟 = × 100% 퐴푐푐푒푝푡푒푑 푉푎푙푢푒

When using the percent error equation, do not be concerned if you get a negative number. This is acceptable. ➢ If your percent error is positive, this means that your measured value is greater than the accepted value. ➢ If your percent error is negative, this means that your measured value is less than the accepted value. Show Your Work Here:

Percent Error for Percent Water in Hydrate = ______

• If a percent error is within 10% (–10% < percent error < 10%), the results are considered reasonably accurate. o This is acceptable accuracy for a high school chemistry lab. • If your percent error is greater than 10% or less than –10%, then the results are not considered accurate.

At this point you need to determine what your sources of error and whether the errors are personal (lack of care and precision in completing measurements) or systematic (there is something wrong with a measuring tool or with the procedure used). a) Based on the calculations you have completed is your percent water reasonably accurate? ______

b) If it is reasonably accurate explain what you did during the experiment ensure good results. If it is not reasonably accurate, propose sources of error, either personal or systematic, that you think contributed to the less accurate results.

______

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