Chemistry Summer Science Institute s1

DAY 2 CHEMISTRY SUMMER SCIENCE INSTITUTE

WHAT’S (the) MATTER? A metal cylinder and the light coming from a flashlight both exist. We can perceive them both. But they have a very different kind of existence! By performing the following 2 simple activities, try and put into words their essential difference! 1. Place the metal cylinder on the digital scale. Remove it. Shine the light on the scale.

Result ______

2. Place about 15.0 mL of tap water in a graduated cylinder. Carefully slide the metal cylinder into the water. What happened to the height of the water in the graduated cylinder?

Why do you think this happened? The essential difference between the metal cylinder (matter) and light (energy) is

Classify each of the following as matter or energy: a) water ______d) the bubbles in soda ______

b) sound ______c) styroform ______

c) air ______f) heat ______

Are there any questions you would like to ask?

1 DAY 2 CHEMISTRY SUMMER SCIENCE INSTITUTE

WHAT’S THE SAME?/WHAT’S DIFFERENT – PART I

Make each of the following observations or perform each of the activities on both table salt

(NaC1) and ethanol (C2H5OH).

ETHANOL SALT (ethyl alcohol)

1) Is it solid, liquid, or gas? ______

2) Color? ______

3) Odor? ______

4a) Find the mass of 2 empty corked Empty tube Empty tube test tubes on the digital balance. ______g ______g

b) Fill with 1 inch of each material ______g ______g and the find mass.

c) Mass per inch of material. ______g/in. ______g/in.

5) Place 2 full spatulas of each in test tube filled with 1/3 water and shake. Record the result. Save this solution for 6 and 7.

6) Place 3 drops of salt solution (salt dissolved in water) and 3 drops of ethanol on 2 separate pyrex watch glasses. Light Bunsen burner and aim at each material. Did it burn?

7) Place 1 inch of salt solution and 1 inch of ethanol in 2 separate test tubes. Place in test tube rack. To both add 1 drop NaOH and 2 drops KMnO4. Shake. Record the results.

WHAT’S THE SAME?/WHAT’S DIFFERENT? – PART I

Questions

If you were given 2 clear colorless solutions, how could you easily tell if one was salt water and one was ethanol?

What is the difference between the first five properties you observed about salt and ethanol, and properties 6 and 7?

WHAT’S THE SAME?/WHAT’S DIFFERENT? – PART II

At this station, you will find a box containing samples of various materials. Take them out of the box and examine them carefully. Are they all made of the same thing? Divide these objects into three separate piles based on what they are made of. List the objects in each pile in the columns below.

Pile #1 Pile #2 Pile #3

List some of the properties or characteristics (color, feel, luster or shininess, density or heaviness) that are THE SAME or COMMOM TO the objects in each of the piles.

Now carefully observe the objects in each of the piles separately. List some of the properties that are DIFFERENT for each object in the pile.

The properties that are the SAME about the members of each group are called INTRINSIC PROPERTIES. List some INTRINSIC PROPERTIES:

The properties that are DIFFERENT about the members of each group are called EXTRINSIC PROPERTIES. List some EXTRINSIC PROPERTIES:

If you had an object and needed to identify what material it was made of, do you think it would be more useful to have a list of intrinsic or extrinsic properties of known materials to help you with the identification? Explain your answer.

Can you think of any problem that might occur in trying to identify materials by their properties?

How would you define the word “property?”

DENSITY

Select a metal cylinder from the box.

What is its color?

A. Mass of cylinder using the digital balance g

Height of cylinder using metric ruler cm

Diameter of cylinder (distance across the round top) using the vernier calipers. Change mm to cm. cm

Radius of cylinder (1/2 diameter) cm

Volume of the cylinder.

2 3 Volumecylinder = p r height cm

(Note: The unit cm3 is the same volume as the unit mL. The value of π is 22/7 or 3.14. Show your work.)

Mass Density = Calculate the density of cylinder: Volume

(Show your work.)

B. You will now measure the volume of this cylinder in a different way. When an object sinks in water, it displaces an amount of water equal to its own volume. Therefore, if we can measure how much water the cylinder pushes out of the way when it sinks, we will know its volume in mL.

Place 15.00 mL of water in a 25 mL graduated cylinder. Carefully slide (with no splashing) the metal cylinder into the water.

What is the volume of the water plus the metal cylinder? mL

What is the volume of the metal cylinder? mL

How does this volume compare to the volume you calculated previously

? What might account for any discrepancies?

Identify the metal the cylinder is made of by comparing your calculated density to the densities in the list below.

Metal Density ( g/cm3) Aluminum 2.7 Copper 8.92 Lead 11.4 Steel 7.8 Brass 8.41

Metal of cylinder?

MATTER: PROPERTIES AND CHANGES

ARE ALL CHANGES THE SAME?

You are now going to bring about some changes in matter. By carefully observing the materials before and after the change, you will try to classify these changes into two types. [Note: Place waste in marked waste bottles after completing each procedure.] 1. Place a spatula-full of table salt in one small beaker and a spatula-full of sand in another beaker. Take a good look at both of them. Pour the sand in with the salt.

Is the salt still present?

Is the sand still present?

Reason for answer

2. Add tap water to the beaker almost up to the top. Stir the contents with a glass rod. Is the salt still in the beaker? Is the sand still in the beaker? Reason for answer 3. Place a spatula-full of solid alum (used to keep pickles crisp) in a pyrex test tube. Attach the tube to a ring stand with a test tube clamp. Gently heat the alum with a Bunsen burner until you see only liquid in the tube. Remove the heat and allow it to cool.

Is the alum still present in the test tube?

Reason for answer

4. Place a spatula-full of copper (II) carbonate (CuCO3) in a pyrex test tube. Attach the tube to a ring stand with a test tube clamp. Heat the CuCO3 with a Bunsen burner until you see no further change. Remove the heat and allow it to cool.

Is the CuCO3 still in the test tube?

Reason for answer

5. Place about a ½ inch of cobalt (II) chloride in a test tube. Add about ½ inch of sodium phosphate solution into the same tube.

What do you see?

Are the salt water and silver nitrate solution the only materials in the tube? ______

Reason for answer

6. Take a wooden splint and break it up into pieces. Are the pieces still wood? 7. Place a wooden splint into the Bunsen burner flame. After a minute or two blow it out.

Is the original wood still present?

Divide the above changes into two categories. List them by number in the chart below.

What is the essential difference between these 2 types of changes that matter can undergo?

______