Experiment 14- Crystal Growth PDF

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Experiment 14: Crystal Growth Required reading: Ebbing, 11th Edition, Chapters 2 and 11. - Ionic substances - Naming simple ionic compounds - The solid state: Crystals and ionic solids - Crystal structures Learning Goals:  To practice nomenclature of simple ionic compounds  To observe how a crystal grows.  To see the physical relationship between a physical crystal and a crystal structure. Background information and theory: In this lab you will be able to observe how a crystal grows and to see the physical relationship between a physical crystal and a crystal structure. The required reading from your textbook will provide background information. You will reach some those pages at the end of the semester. It can take several months to grow crystals but in this lab we will do a quick method to grow borax crystals. In the following video you will learn about unit cells in crystals: https://www.youtube.com/watch?v=KNgRBqj9FS8 The following YouTube sites provide further background: DIY Crystal at Home (2) - Copper(II) Sulfate https://www.youtube.com/watch?v=k3nClG-DT7w How to grow beautiful crystals of salt - do your chemical experiment! https://www.youtube.com/watch?v=FKCS1DvORug How To Make Your Own Salt Blue Crystal - Amazing Science Experiments with Home Science https://www.youtube.com/watch?v=yEcIUxqRn5g Materials : Borax Warm water String 2 pencils Pipe cleaners Large bowl Scissors 2 identical jars Cooking pot Tablespoon

SDS on chemicals: Borax (sodium tetraborate decahydrate) is harmful if swallowed, causes skin and eye irritation. Avoid inhaling the compound as it may cause membrane irritation. Handle with gloves. Procedure: Part 1 1) Watch the following video: https://www.youtube.com/watch?v=FFR4nei9qv8 2) Collect the information from the video in the data pages. Part 2: AT HOME * All experiments at home must be done carefully. * Avoid touching hot substances to prevent injuries due to physical burn. * Use goggles at all times to avoid eye injury. *You may use gloves if available. * If you get a reagent in your skin or eyes flush for at least 15 minutes with running water. * Keep your experiment away from people not doing the experiment. * Do not leave your experiment unsupervised. * Do not ingest any of the chemicals used. *Label your substances *Clean up quickly once you finish your experiment. *If using anything from your kitchen, be sure to thoroughly wash and dry before next use. This

procedure

was

adapted

from

https://www.20muleteamlaundry.com/uses/arts-

crafts/crystals-for-diy-home-crafts/

How to Create Crystals with Borax

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1. Create shapes Use the pipe cleaners to create the foundation of your crystals for the experiment. Take the pipe cleaners and mold them into whatever shape you want the crystals to turn out as, these will form the basis for your creation. Be sure to select the color of your pipe cleaners purposefully. Because Borax crystals is white, the crystals will form clear, so the pipe cleaners underneath will give them their color. To make your own colorful creations, be sure to pick the brightest colors for your pipe cleaners! 2. Boil water Take your pot and bring the water back up to boiling point. This is where you’ll dissolve your Borax mixture. It’s up to you how much water to use, but 3 cups should contain enough Borax to complete the experiment. Feel free to add more if need be. 3. Mix solution

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Add about 3-4 Tbsp of Borax for every cup of water in your solution. Stir until the Borax dissolves in the water. You want the water to be clear because if the water gets cloudy then your crystals will be cloudy. 4. Pour into jars Once your solution is mixed, pour into the mason jars about three quarters of the way to the top. 5. Suspend pipe cleaners Use the string to tie your pipe cleaners to the pencils. Then place these pencils over the rim of each jar so that the pipe cleaners are suspended in the water. Be sure to thoroughly wash and dry hands. 6. Leave overnight The submerged pipe cleaners should form crystals over the next 12-24 hours. The longer that you leave them then the bigger they will grow. Be sure that none of the pipe cleaners are touching each other or the sides of the jars so that they can grow as large as possible. 7. Remove and dry crystals The crystals should have grown around the colored pipe. Now, simply take them out of the jars and let them dry and marvel in your crystal creations! 8. Share your results Now that you know how to make your own crystals, take a picture of your crystal and add it to your report. Write a paragraph explaining your observations and comments about this experiment (data section).

Name: _________Judy Pham_____________ Crystal Growth Data Collect the following information from the video and complete the calculations indicated below. 1) According to the video, is the initial water used cold or hot? Why do you think the temperature of the water is relevant? (Hint: What happens with the solubility of the salt when the temperature of the water changes?)  The initial water is hot because when salt is cooled, the solubility reduces. 2) According to the video, the first solution is filtered. Why?  To get rid of solid impurities 3) According to the video, what can happen if the beaker is not covered with foil?  Dust particles could get in it. 4) According to the video, how long does it take for the crystal growth process to occur? (minutes, hours, etc.)  Hours 5) Observe the final crystal in the video. How would you describe the physical properties of the crystal?  Blue, rigid, cool, big 6) A seed of CuSO4.5H2O with a mass of 0.500 g was carefully placed into a saturated solution of copper (II) sulfate. After 7 days the mass of the seed crystal was determined to be 0.648 g. After 14 days the mass of the crystal increased to 0.899 g and after 21 days the mass of the crystal was found to be 1.081 g. Make a plot of mass vs time (days) and extrapolate to predict what would be the mass of the crystal in 28 days if the growth is linear. Include labels and units on each axis.

1) AT HOME: Write your observations and comments about the crystal growth you did at home.

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I waited about one day for the crystals to form. After the first few hours, I saw some crystals forming, but I wanted to wait longer for a better result.

2) Add a picture of your crystal here.

Name: __________Judy Pham____________ Crystal Growth Postlab questions: Your instructor may ask you to answer these in your lab notebook, or to answer directly on this page and turn it in, or to include these answers in a formal lab report. Follow your instructor’s directions. Using the following data answer the questions below. Pay special attention to significant digits. Data table Crystal growth Mass of the initial seed Concentration of the copper(II) sulfate solution Volume of copper(II) sulfate solution used Mass of the final crystal

0.825 grams 0.100 M 96.50 mL 3.176 grams

1) How many grams of solute from the solution was incorporated to your original seed? (final crystal mass-initial crystal mass) 

2.351g

2) How many moles of solute from the solution were incorporated to the original seed? (Use the molar mass of the copper (II) sulfate pentahydrate to transform the grams found in question 1) 

0.2351M

3) How many moles of copper (II) sulfate were available in the solution? (You need to calculate the moles of solute present in the initial solution by using the initial volume and concentration (moles=MxV)) (Show all your work) 

0.100x96.50 = 9.65M

4) What percentage of the copper sulfate from the solution was incorporated into the seed? (What is the % recovery from the solution?). Show all your work. % recovery= (Moles incorporated/moles available)x100% 

235.1%...