What Two Substances Make up the Mystery Mixture? How Do You Identify a Substance?

Name: ______Period: ______Date: ______Mystery Mixture

Background: There are millions of different substances in the world. For the next few weeks we will be investigating the properties and composition of a few of them . The study of substances and their interactions is chemistry. At the start of this lab, you are going to be given a white powder, of unknown composition, unknown to you and me. We only know that it is a safe mixture of two substances. Your task is to analyze and identify what the two substances are. The foundation of scientific investigation is careful, precise observation. Methodically observe all aspects of the substance. Go slowly. Take your time. Do not rush to complete the steps. Rushing causes you to miss the small details that often make the biggest difference.

Question: What two substances make up the mystery mixture? How do you identify a substance?

Materials: 5 mL of mystery mixture 2 hand lenses 1 plastic cup, 250 mL 1 cup of water 2 pipettes Protective eyewear

Part One: Observe 1. Place 5 mL of mystery mixture in the plastic cup. 2. Carefully observe the mixture. Do not touch or taste. 3. Record your observations. 4. Compare and discuss your observations with another group.

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Part Two: Add water 1. Add one pipette of water to the mystery mixture. Do not use the pipette to stir the mixture. 2. Observe. 3. Take turns adding additional pipettes of water, pausing to observe as you go. 4. Record your observations. 5. Compare and discuss your observations with another group.

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Discussion and Conclusions: Name: ______Period: ______Date: ______White Substance Information

Background: A substance is a form of matter. There are millions of different substances on Earth, each different from every other substance. Each of the vials you will use in this lab contains a different pure substance…no mixtures. Observe and become familiar with each substance, their names, and their properties. Two of these substances make up the mystery mixture. Your task is to identify which of these substances are form the mystery mixture. The label has three ways to identify each substance. The top line is the chemical name. The second line (in parentheses) is the common name for the substance. The third line is the chemical formula. Chemical formulas are used to easily identify the elements and the proportions of those elements used in making a compound. Chemical formulas will be taught in great detail later.

You will need to use the information sheets provided to you, as well as your laboratory investigations, to complete the following table. As mentioned in earlier labs, careful and patient observations pay off.

Chemical Chemical Common Uses Name Formula Name Observations before water Observations after water

Look for patterns in the chemical formulas and chemical names of the substances. What patterns do you see? Can you read the chemical formula based on these patterns?

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Notes: Summary Questions:

1. Which substances do you think might be in the mystery mixture?

2. What evidence do you have to support these hypotheses?

3. What additional evidence would help you to prove your hypothesis? Name: ______Period: ______Date: ______Two Substance Reactions

Background: A substance is material with specific physical and chemical properties. Physical properties include such things as taste, smell, color, shape, luster, melting point, boiling point, etc. Chemical properties have to do with what happens when you mix that substance with other substances. For instance, when you mix oil and water they remain separated. That same oil and water should always separate when mixed…that is one of their properties. A mixture is a combination of substances that are physically combined. They do not create a new substance and still have the same individual properties they had before you mixed them together. Consider a mixture to be like a fruit salad. You put a bunch of different types of fruit in and, when you take a bite, you taste all the different fruits, not something totally different. Do not rush!!! Mix two substances in a well, test, and record your observations. Then, test a separate hypothesis. You should be able to, at any time, identify which substances were being tested in which well.

Question: Which two substances make up the mystery mixture?

Materials: 1 1 Set of nine white substances Minispoons, green 0 1 Vial of mystery mixture 2 Well trays 2 Dropper bottles of water  Protective eyewear

Procedure a. Put one level minispoon of two different substances (or two minispoons of ONE substance) in a well. It is important you record the number of the well you are observing. b. Add 10 drops of water. Observe and record.

Well Substance Substance Numbe Results 1 2 r 1

Notes: Summary Questions:

1. Which two substances do you think make up the mystery mixture? Please list your evidence. This should be very helpful in completing your CTQs.

2. When you added water to the mystery mixture (and other mixtures), bubbles were produced. What are bubbles?

3. Where did the bubbles come from?

Discussion: (view evaporation tests on FOSSWeb at this point!!)

What is a chemical reaction? How do you know a chemical reaction has occurred? How is this different than two mixed substances? Critical Thinking Questions (CTQs)

At this point, you have done two separate labs and some research into the identity of the mystery mixture. You are now ready for your first set of Chemistry CTQs. These are the same as those for the PS labs, but with one catch. You are now not using the data from one investigation, but a series of three small investigations (mystery mixture, white powder research, and two substance reactions) to make ONE CLAIM about the identity of the mystery mixture. It will require using data from ALL THREE INVESTIGATIONS to make your claim. We will allow some time in class for you to compare observations with other groups, repeat and confirm your data (if necessary), and create claims you are confident are correct. Name: ______Period: ______Date: ______Reaction in a Bag

Background: A chemical reaction is when the interaction of two or more substances creates one or more new substances. In the mystery mixture labs, you combined two substances, added water (a third substance) and the result was, among other things, the creation of a gas. Since you put a liquid and two powders in the well, this substance (with new properties) had to have been a new substance. The substances you put into the well are referred to as the reactants, the starting substances. The resulting substances after a reaction takes place are called the products. Today you will be observing the physical properties of the reactants and the products.

Question: What kinds of changes might be indicators of a chemical reaction?

Materials: 30 30g Calcium chloride (CaCl ) Sodium Bicarbonate (NaHCO ) g 2 3 30 2-5 mL Water Bromothymol Blue (BTB) g 1 Plastic bag  Protective eyewear and aprons

Procedure: 1. Observe the physical properties of each of the reactants (the starting substances). Record your observations in table 1-1. 2. Mass each of the substances and record the mass in table 1-1. Mass of the bag:

TABLE 1-1: PHYSICAL PROPERTIES OF REACTANTS

Substance CaCl2 NaHCO3 H20 BTB TOTAL MASS Physical Properties

OF REACTANTS

Mass of Substance

3. Predict what will happen when we combine all the ingredients in the bag. Write your prediction here.

4. Pour 30 grams of Calcium chloride in the plastic bag. 5. Pour 30 grams of Sodium bicarbonate into the plastic bag. Seal and mix thoroughly. 6. Add the BTB to the water (in a beaker). Stir.

At this point, the last few steps will happen very quickly. Read the steps five through eight completely before moving on so you can do it all at once.

7. Pour the water/BTB mixture into the bag. Seal quickly and completely. Shake continuously to mix the ingredients while the reaction is occurring. 8. Observe the reaction and record your observations. Remember to be thorough.

Observations during the chemical reaction: 9. Observe and record the physical properties of the products of the reaction.

TABLE 1-2: PHYSICAL PROPERTIES OF PRODUCTS Physical Properties of the Products

10. Mass the bag and the products (substances produced in the reaction). Record the mass of your products in table 1-3.

Mass of the bag and the products Mass of the bag (from step 2)

MASS OF PRODUCTS

11. Compare your observations to those of other groups. 12. Don’t forget to clean up (using plenty of cleaner, not just towels).

Summary Questions:

1. How did the mass of your products (the end substances) compare to the mass of your reactants (the starting substances)?

2. Justify/Explain possible reasons for this comparison of the starting and ending masses. Discussion and Notes: (Products and reactants, and energy in a chemical reaction will be discussed)

Level II ideas:

1. Recreate this investigation with a different amount of one substance and compare the results to this investigation. For instance, how does the presence of more sodium bicarbonate affect the outcome? Name: ______Period: ______Date: ______Mystery Mixture Elements

Part 1. Identifying elements Substance Chemical Formula Elements

Calcium carbonate CaC03

Sodium carbonate Na2CO3

Sodium bicarbonate NaHCO3

Magnesium sulfate MgSO4

Calcium chloride CaCl2 Sodium chloride NaCl

Ascorbic acid C6H8O6

Citric acid C6H8O7

Sucrose C12H22O11

Part 2. Questions 1. Which substance has the greatest number of elements? ______How many? ______

2. Altogether, how many different elements are in the nine substances? ______

3. Which element is found in the greatest number of substances? ______

4. How many elements are in the substance carbon dioxide? ______

5. How many elements are in the substance water? ______

6. Which of the nine substances are made of two elements? ______

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7. Which of the nine substances are made of three elements? ______

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8. Which of the nine substances are made of four elements? ______

______Name: ______Period: ______Date: ______“Elements” Questions

1. What is an element?

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2. How are matter and elements related?

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3. How was Mendeleyev able to predict the existence of elements that had not yet been discovered?

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4. What is the periodic table of elements?

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Discussion and Notes: Name: ______Period: ______Date: ______Elements in Products

Part 1. List the elements found in several products.

Product Name Elements

Part 2. Analyze the elements in the products.

1. How many different elements did you find in the all the products you investigated?

______2. What is the most common element in the products you investigated?

______3. How many metals did you find in the products you investigated? List them.

______Name: ______Period: ______Date: ______The Periodic Table

Name: ______Period: ______Date: ______The 50 Most Common Elements

The Periodic Table of Elements is a way of displaying the fundamental substances called elements. Each box has a different element. As you can see, there are over 100 elements. Only the first 90 or so are naturally occurring. The rest are created only in labs. Elements are the basic building blocks of matter. Everything on Earth that has mass and takes up space is made of elements. All substances are made of elements. Notice that all elements have a specific symbol and atomic number. During this chemistry unit, you are going to be asked to memorize the name, symbol, and atomic number of the 50 elements highlighted below. They are the most common 50 elements on Earth. The purpose is to make you familiar with them as you will be dealing with them throughout high school and years after.

Many students have found it helpful to highlight the elements in groups of 10 so they remember which elements are tested together. Some have also found it helpful to create flashcards or use quizzes on websites like FOSSWeb and Freerice.com Name: ______Period: ______Date: ______Response Sheet - Elements

Carla studied the ingredients on a box of cereal. She made a list of the elements she found. She told her friend,

This cereal contains eight different elements. I wonder what the rest of the cereal is made of.

If you were Carla’s friend, what would you tell her?

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Notes: Name: ______Period: ______Date: ______“Elements in the Universe” Questions

1. What element is among the five most abundant elements in the Sun, Earth, ocean, atmosphere, and organisms? ______

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2. What does it mean when people say that everything is made of stardust?

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3. Why are the elements carbon, hydrogen, oxygen, and nitrogen important to life on Earth? ______

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4. How can there be so many different substances in the world if there are only a few elements that are common? ______

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______Name: ______Period: ______Date: ______How Much Gas? Part A

Background: In earlier investigations, you observed chemical reactions and the products of those reactions, including gas. In this investigation, you will be observing the gas in greater detail. You will start by making a 100 mL stock solution of citric acid. This is simply a supply from which you will draw a small amount for each trial. You will repeat this experiment THREE (3) times and calculate the average result.

Materials 1 Jar of sodium bicarbonate 2 Rubber stoppers, #1, with hole 1 Jar of citric acid 2 Syringes, 35-mL 2 Spoons, 2-mL 1 Waste container 1 Plastic cup 1 Tray or basin 1 Stirring stick  Water 2 Glass bottles  Graduated cylinder  Protective eyewear

Procedure a. Gather the necessary materials for your group. b. Get a bottle-and-syringe system for each pair. c. Put on protective eyewear. d. Read all of the following directions before starting. e. Make a stock citric acid solution. Dissolve one level, 2-mL spoon of citric acid in 100 mL of water. This is your stock citric acid solution. f. Put on level, 2-mL spoon of sodium bicarbonate into the bottle. Twist the stopper onto the bottle. g. Take up exactly 5 mL of citric acid solution in the syringe. Insert the tip of the syringe into the hole of the bottle. h. In one smooth, quick motion, push the solution into the bottle. Don’t remove the syringe. Observe and record. i. Dump the used experiment and conduct two more trials. It is not necessary to wash out the bottle between trials. Results:

Questions for your group to discuss: 1. On average, how much gas formed when the citric acid and sodium bicarbonate reacted?

2. How much sodium bicarbonate was in the reaction bottle?

3. How much citric acid was in the reaction bottle?

4. How much citric acid did you add to the stock solution bottle?

5. How much stock solution did you add to the reaction bottle?

6. How much citric acid was in the 5 mL sample you pulled out of the stock solution bottle? Name: ______Period: ______Date: ______How Much Gas? Part B

Analysis/Summary of Lab 1. What caused the syringe plunger to go up during the reaction between citric acid and sodium bicarbonate? ______

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2. Why is the syringe more useful than a balloon to conduct this experiment? ______

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3. What do you think might happen if you doubled the amount of citric acid? Why? ______

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4. What do you think might happen if you double the amount of sodium bicarbonate? Why? ______

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______Discussion and Notes: Name: ______Period: ______Date: ______What’s in the Bubbles?

1. Make a list of the gases you know about or have heard about. ______

2. How would you define gas? ______

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3. Everything is made of elements (see your earlier work). What elements could be in the gas that

forms when sodium bicarbonate (NaHCO3) and citric acid (C6H8O7) react? ______

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______4. What gas do you think is in the bubbles that form when NaHCO3 and C6H8O7 react? ______

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Discussion and Notes: Name: ______Period: ______Date: ______Discuss Air as Particles

This section of questions refers to the experiment involving a piece of bubble wrap and syringe.

1. What is the air in the syringe (recent observations) and the air in the bubbles (well tray) made of?

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2. What happens to the gas particles in the syringe when you push on the plunger?

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3. What happens to the air particles in the bubble when you pull up on the plunger?

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4. Are there more air particles in the bubble when it is compressed or when it is expanded?

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5. When you push on the plunger, are the air particles closer together in the syringe or in the bubble?

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6. What is between the air particles?

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7. What happens to air particles when a volume of air is compressed?

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When a volume of air expands?

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Name: ______Period: ______Date: ______Air in the Syringe A

Name: ______Period: ______Date: ______Air as Particles B

1. How are the particles in syringe B drawn differently? Why did you draw them this way? ______

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2. How are the particles in syringe C drawn differently? Why did you draw them this way?

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3. How are the particles in syringe D drawn differently? Why did you draw them this way?

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4. How are the particles in syringe E drawn differently? Why did you draw them this way?

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5. Which illustration demonstrates air that is being compressed?

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Air that is being expanded?

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Discussion and Notes: (Compression, expansion, and pressure will be discussed. You might choose to include drawings and explanations)