Matter-Naming-Solutions unit

4. Place approximately 5 ml of vinegar into a clean beaker and add 20 ml of water. Add a small amount of sodium
chloride (salt) to the vinegar and mix carefully. Record your observations. Add one dirty penny to the beaker with
the mixture in it and swirl for a minute or two. Remove the penny and record your observations.

5. Obtain a small sample of CuCl2 and add it to a 100 ml beaker that has about 20 ml of water. Without stirring,
record your observations of the mixture. Observe both the crystals and the water.

5a. Stir the mixture with a glass rod until the crystals are completely dissolved. Record your observations
of the solution.

5b. Place a thermometer in the solution and record the temperature. Loosely crumple a small sample of aluminum foil
into a ball. Place the ball in the solution and record your observations. CAUTION: Observe the mixture from the
side, DO NOT look directly down into the beaker. Continue to observe the mixture for at least 5 minutes, and note
any change in temperature. Does stirring of the mixture have any effect on the reaction?

Observations for part A:

1. What did you observe as the candle burned?

What was left after the candle burned for the entire period?

List three physical changes and three chemical changes that occur when the candle burns.

2. What did you observe when you added the salt to the water in the test tube and shook it?

What did your observe when the silver nitrate was added to the salt water?

3. What did you observe when the hydrochloric acid was added to the magnesium metal?


 


 

 

51

Observations for part B:

1. What did you observe when you mixed the iron and sulfur?
What happened when the magnet was passed beneath the mixture?
2. What did you observe when you mixed the salt and sand on the filter paper?
What did your observe when the mixture was added to the water?
3. What did you observe when you mixed the dry citric acid and sodium bicarbonate?
What happened when the mixture was placed in the beaker of water?

4. What observations did you make when you added the salt to the vinegar and mixed the two?
What happened to the penny when it was placed in the vinegar/salt mixture?

5. What observations did you make when you just added the copper chloride to the water?
What observations were made after you stirred the two?
6. What was the temperature of the solution before you added the aluminum foil?
What observations were made after the foil was added to the solution?


 

52

“FreeSI”
 –
 Freeman’s
 Scientific
 Investigation
 

Objectives:
You will perform a series of tests to determine physical and chemical properties of several powders
You will utilize your test results to identify an unknown substance

Background Information:
Nada High School has a drug problem. Over the past year, illegal drugs have been seized from students’ lockers on five
occasions. All of these illegal drugs are white powders that look remarkably like table salt. During a recent locker search,
investigators collected several bags filled with a white powder. Before charges can be pressed on the individuals in possession, the
identity of the powders must be established.
You are a member of a forensic science lab team that has been sent to Nada High School. A temporary lab facility has been
prepared at the high school. The unknown white powders are delivered to you in the lab so you can determine their identity.
Due to limitations in equipment at the school, you have been asked to use a simple series of tests to determine the identity of
the powders. To enable you to do this, six white powders have been provided. You will run tests on each of the six powders and
record your results. Later you will compare results with those from test of unknown powders collected during locker seizures.
Your findings will determine the charges (if any) brought against the students in possession of drugs.

An overview of the white powders previously discovered at Nada High School includes the following:

Brograine: Mild hallucinogen. First offense is usually probation.
Speclate: Mild stimulant; often results in psychological dependence. First offense results in 6 months to 1 year in prison.
Rotaran: Strong stimulant; causes physical dependence. First offense results in 1 year to 3 years in prison.
Barrop: Moderate depressant; causes physical dependence. First offense results in 1 year to 3 years in prison.
Lixonin: Strong narcotic that causes physical and psychological dependence. First offense results in 5 year to 10 years in prison.
Table salt: Found in one student’s locker as a joke. Prank resulted in expulsion from school.

Procedure, Part A:
Developing a positive test for the six known powders

1. Record your results for test conducted on the six known powders in Data Table 1. If nothing happens
in a specific test on a known substance, record ND (No Data) in the proper location on the data table. At
the end of Part A, you should have something written in each box on the chart. Be descriptive.
2. Place a pea-sized sample of sample A on the black-bottomed petri dish, close the sample bag and
return it to the large evidence bag, and observe its appearance (color and texture) with a hand lens.
Record your results.
3. Place a spatula tip-sized s a m p l e o f A in the reaction plate (use some from the petri dish). Add 10
drops of REAGENT A to the reaction plate. Record your observations.
4. Half fill test tube A with tap water. Place a spatula tip-sized sample of sample A (from the petri dish) in
a test tube. Cover the test tube and shake for a few seconds. Record your observations. Do not dispose
of the sample. You will use it in the next step.
5. Using the test tube from step 4, add 15 drops of REAGENT B to the test tube. Observe and record what
occurs in the test tube.
6. Place a spatula-sized sample of the powder (from the petri dish) in the reaction plate. Add 5 drops
of REAGENT C to the sample. Record your results. Thoroughly clean and return the test tube to the
beaker.
7. Repeat steps 2-6 for samples B through F (one at a time).

53

Procedure, Part B:
Identification of unknown substance

You now have the test results for each white powder on Data Table 1. These results will help you to determine the identity of an
unknown substance by comparison. Several unknown substances were discovered in student lockers today. Different forensic
teams have been asked to identify some of the unknowns. In Data Table 2, write down the number of the beaker whose contents
you will analyze. This number indicates the locker from which the powder was taken. Compare your results with those in Data
Table 1 to determine what substance the students had in his or her locker. Be careful; your results will determine whether or not
charges should be pressed against the student.

1. Write down the locker number on the sample in Data Table 2

2. Perform all the tests you performed in Part A on this unknown substance. Record your findings on Data Table 2.

3. Compare the results in Data Table 2 with the results in Data Table 1.

Data Table for Part A:

Substance Color Texture Addition of Addition of Addition of Addition of

REAGENT A Water REAGENT B REAGENT C

A – Brogaine

B – Speclate

C – Rotaran

D – Barrop

E – Lixonin

F – Table Salt

Data Table for Part B: Texture Addition of Addition of Addition of Addition of
Color REAGENT A Water

REAGENT B REAGENT C

Unknown
Sample
#

Which one of the substances from Part A do you think your unknown sample is? Explain using data!


 

54

“Making”
 Ionic
 Compounds
 Lab
 

PURPOSE - To mix solutions containing cations and anions to make ionic precipitates.

MATERIALS ten solutions in dropper pipets labeled 1-6 and A-D two 12-well Chemplates

PROCEDURE

1. Set up the two Chemplates so they are next to each other vertically (large oval well at the top). This will allow for the set up to

have 6 horizontal wells and four vertical wells.

2. Add 3 drops of the lettered or numbered solutions as listed in the table below. For example, the upper-left well should have 3
drops of solution 1 and 3 drops of solution A. Below that, there should be 3 drops of solution 1 mixed with 3 drops of solution B.

Repeat these mixtures for each of the 24 wells. (see the diagram below)

3. For each of the mixtures that forms a precipitate (gets cloudy or see a solid forming), you are to write the name and formula of the
ionic compound formed. Here are the ions you are mixing:
cations 1 – silver ions, 2 – lead (II) ions, 3 – calcium ions, 4 – iron (III) ions, 5 – magnesium ions, 6 – copper (II) ions
anions A – carbonate ions, B – phosphate ions, C – hydroxide ions, D – sulfate ions

When you mix 1 with A, a white precipitate that is silver carbonate (Ag2CO3) is formed. Place a check mark by the combinations
that form precipitates and write the name and formula for those combinations only in the analysis and conclusions table below.

1✔A 2A 3A 4A 5A 6A ANALYSIS AND CONCLUSIONS
4B 5B 6B
1B 2B 3B Write the name and formula of all compounds that form
precipitates. If no precipitate forms, leave them blank.

1C 2C 3C 4C 5C 6C Ag CO → Ag COsilver io+n carbonate2i-on
1D 2D 3D 4D 5D 6D 3
silver carbonate

23

Mix Name Formula Mix Name Formula

1A silver carbonate Ag2CO3 1C
2A 2C

3A 3C

4A 4C

5A 5C

6A 6C

1B 1D

2B 2D

3B 3D

4B 4D

5B 5D

6B 6D

55

Rate
 of
 Dissolving
 Lab
 

Purpose

This lab will help you identify factors that affect the rate at which substances dissolve.

Procedure

Part A: Temperature
1. Pour 200 mL of tap water into one cup and 200 mL of hot water into a second cup. Label each cup. Record
the temperature of each cup.
2. Add one sugar cube to each cup and stir both at the same speed. Record how long it takes for each to
dissolve.

Part B: Surface Area
1. Pour 200 mL of tap water into two labeled cups.
2. Add one sugar cube to one cup and sugar packet to the other cup.
3. Stir both mixtures at the same speed until dissolved. Record how long it takes for each to dissolve.

Part C: Stirring
1. Put equal amounts of tap water in two separate labeled cups and add one sugar cube to each cup.
2. Stir one cup quickly and one cup slowly. Record how long it takes for each to dissolve.

Data Tables:

Part A: How does temperature affect the rate of dissolving?

Beaker Temperature Rate of Dissolving Observations
Cool

Warm

Part B: How does surface area the rate of dissolving?

Beaker Size of Solvent Rate of Dissolving Observations

1 Small Particles
(sugar packet)

2 Large Particles
(sugar cube)

56

Part C: How does stirring a mixture affect the rate of dissolving?
Beaker Stirring the Mixture? Rate of Dissolving Observations
1 Yes
2 No
List three factors that affect how quickly a solute dissolves in a solvent.
Which factor(s) cause the rate of dissolving to increase?
When testing the effect of particle size on dissolving, what other variables need to be controlled?
When testing the effect of stirring on dissolving, how did you control other variables?


 

57

Molarity
 of
 Lemonade
 Lab
 

Background Information
We will be making 5 different concentration of lemonade (0.1 M, 0.3 M, 0.5 M, 0.7 M, and 1.0M).
You will taste the lemonade solutions you make to determine how you like your lemonade.

For this lab, we are going to assume the lemonade powder is mostly sugar (C6H12O6) with added color
and flavorings. You can assume the mass of lemonade is that of sugar.

Pre-Lab Questions: Show your work for each calculation and draw a box around your final answer.
Use correct units.

1. The molar mass of lemonade mix is assumed to be 180 g/mol.
To calculate the mass of mix needed, you multiply the molar mass (g/mol) by the molarity (mol/L) by
the volume (0.1 L).
Ex. If you wanted 100 mL (0.1 L) of 0.1 M lemonade, the calculation is as follows:

180 × 0.1 ×0.1 = 1.8        (  100      )
1 1

2. Calculate the mass (in grams) of lemonade to make 0.1 L solutions of the following
concentrations:
a. 0.1 M – see above equation

b. 0.3 M

c. 0.5 M

d. 0.7 M

e. 1.0 M

3. When lemonade mix is dissolved in water, what is the solute and what is the solvent?

58

**SAFETY**: Normally in the chemistry laboratory there is NO eating or drinking. However, for this

lab we will taste lemonade solutions in order to learn about concentration. Special care must be taken

so that nothing becomes contaminated.

• If at anytime you do not want to taste the solutions, you do not have to!
• Do NOT pour the lemonade powder back in the container if you pour out too much. Dispose

of it in the trash can.
• If any lemonade powder touches the lab bench or balance, dispose of it.

Procedure

1. Obtain 5 cups. With a sharpie marker, label the cups with the following concentrations: 0.1 M,
0.3 M, 0.5 M, 0.7 M, and 1.0 M

2. Each group member will be responsible for making at least one solution. Decide who is making
which solutions. If you have less than 5 people in your group, someone will make 2 solutions.

3. Mark the 0.1 L mark on the cup by measuring 4.0 cm from the bottom of the cup and
drawing a line with the marker.

4. Weigh out the correct amount of lemonade powder in each cup by putting your cup on the
balance, taring the mass to zero, and putting the correct mass of lemonade powder into the cup.

5. Add water to the cup until you have 0.1 L of solution (fill it up to the line you drew).
6. Stir with straw.
7. Observe and taste the solutions you have made. You can have a “designated taster” or you can

pour a little of the solution into separate cups for each group member to taste. Record how
each solution looked, smelled, and tasted. Rate the taste of the solution on a scale of 1 to 5
(5 being the best).

Date Table

Concentration Color Smell Taste Rating (1-5)

0.1 M

0.3 M

0.5 M

0.7 M

1.0 M


 

 

59

Questions

1. Which concentration of lemonade did you prefer the most? What was wrong with the
other solutions that you made?

2. Calculate the molarity of lemonade as prepared using the instructions on the back of the

container. The directions read: Add 88 grams (3/4 cup) of lemonade powder to 1 quart of

water. ( 1 quart = 946.35 mL). Use the following equation:
1   1
88        × 180   × 0.94635 = _______

3. How is taste related to concentration? Why are they related this way?


 

 

60

Beverage
 Density
 Lab
 

Adapted from Flinn ChemTopic™ Labs
Sugar Content Analysis

Introduction
Have you ever been to the ocean? Does it seem that you can float or swim much easier in the ocean than
in a swimming pool? Seawater is denser than freshwater due to the presence of dissolved salt in the ocean.
As a result, our buoyancy – ability to float – is greater in salt water than in plain water. What factors
determine the density of a solution? Can the density of a solution be used to determine how much of a
particular substance is dissolved in it?

Background
The density of a pure substance is a characteristic physical property that can be used to identify the
substance. Density is defined as the ratio of mass per unit volume (D = m/V). It is an “intensive” property,
that is, it does not depend on the amount of the substance. Measuring its mass and volume and then
dividing the mass of the volume determine the density of any material. The mass of a substance can be
measured directly using a balance. The volume of a liquid can also be measured directly using special
laboratory glassware, such as a graduated cylinder, a buret, or a pipet. In this experiment, liquid volumes
will be measured using a graduated cylinder.

The density of a solution depends on its concentration, that is, how much solute (solid) is dissolved in the
solvent (liquid). The higher the concentration of solute, the greater the density of the solution is. A
convenient way to express concentration is in units of weight percent, which corresponds to the number of
grams of solute that are present in 100 g of solution. A 20% salt solution is prepared by dissolving 20 g of
sodium chloride in 80 g of water. (Notice that the final mass of the solution is 100 grams.) If the density
of a solution is plotted on a graph against the concentration of solute, a regular pattern is evident. Density
is directly proportional to concentration. A 20% salt solution, for example, has a greater density than a
10% salt solution. If the densities of several solutions of known concentration are determined
experimentally, a calibration curve (graph) can be constructed that shows a straight- line relationship
between the density of a solution and the concentration of solute. The calibration curve can then be used
to find the concentration of solute in an unknown solution.

Experiment Overview
The purpose of this experiment is to determine the percent sugar content in beverages. The density of five
sugar “reference” solutions will be measured in Part A. The reference solutions contain known amounts of
sugar (0-20%) and have been dyed with food coloring to make it easier to tell them apart. Their densities
will be plotted on a graph to obtain a calibration curve of density versus percent sugar concentration. In
Part B, the densities of two beverages will also be determined and the calibration curve used to find how
much sugar they contain.
The results will be compared again the information provided on the nutrition labels for these beverages.

61

Pre-Lab Questions (these must be done and checked with the instructor first!)
1. Calculate the density of a solution with a mass of 12.53 g and a volume of 8.27 mL.
(D = m/v)

2. According to its nutrition label, orange soda contains 49 g of sugar per 355-mL serving.
If the density of the beverage is 1.043 g/mL, what is the percent sugar concentration in orange
soda?

First, use the density to convert the 355-mL serving size to grams.
Densitysoda(g/mL) ×
volumesoda(mL) = masssoda(g)
Then calculate percent sugar in the beverage.
masssugar(g)/masssoda(g) ×
100 = % sugar

62

Materials Beverages (juice, soda, sports drink)
Water
Beaker, 100 mL or 50 mL
Sugar Balance
Plastic cups

Graduated cylinder, 50 mL and 10 mL

Reading A Meniscus
For exacting measurements of liquids in graduated cylinders, pipets, burets, and volumetric flasks, the

solution’s volume is read at the bottom of the meniscus. Read with the eye horizontal to the liquid’s surface (see
illustration below, left side).

A clear or transparent liquid is read more easily by positioning the top edge of a black mark (made on a white
card) just below the level portion of the liquid. The black background reflects off the bottom of the meniscus

and better defines the liquid’s level (illus. below, right side). Substituting a finger for the black mark on the
white card will work, but it is not as effective.

Procedure
Part A. Creating “Standard” Reference Solutions

1. To make “standard” sugar solutions:
a. Measure all water samples using a graduated cylinder.

b. To get mass of sugar sample, place an empty cup on the balance and hit the “tare” or “rezero” button. Then,
add the amount given below. If your samples are NOT exactly the amount, it is okay, just write down the actual

mass of the sugar to two decimal places. Write all masses in Data Table A.
c. Add the water to the massed sugar in the cup and then mix well with a stirring rod. Label the cup with the

percent sugar solution.

Data Table A Actual mass of sugar (g) Actual % sugar
(actual mass of sugar/actual mL H2O)
Percent Sugar solution
(mass sugar (g)/volume H2O (mL))
0% (0.00 g sugar/50.0 mL H2O)
5% (2.50 g sugar/47.5 mL H2O))
10% (5.00 g sugar/45.0 mL H2O))
15% (7.50 g sugar/42.5 mL H2O))
20% (10.00 g sugar/40.0 mL H2O))

63

Part B. Density of Reference Solutions
1. Place an empty 100-mL beaker on the balance and hit the “tare” or “rezero” button.

The balance should read 0.00 g.
2. Fill a 10 mL graduated cylinder so the bottom of the meniscus (curve) is right on the

10.00 mL mark with 0% sugar (water) and transfer the liquid to the empty beaker.
3. Record the mass of the solution in Data Table B.

4. Re-zero the balance using the tare button.
5. Dump the solution into the sink; rinse and dry the beaker.

6. Repeat steps 2-5 for the other four sugar solutions, proceeding in order from the least concentrated to the
most concentrated.

7. Calculate the density of each solution and record the value in Data Table 1. Density = m/v, so you divide the
mass of the sample by the volume!

Data Table B – Density of Reference Solutions

Sugar Solution Mass, g Sample Volume, mL Density, g/mL
10.00
0% 10.00
10.00
5% 10.00
10.00
10%

15%

20%

Part C. Beverage Densities
Use the procedure in Part B (steps 1-7) to determine the density of the beverages available. Use clean glassware

and record all mass and volume data in Data Table C. Rinse the graduated cylinder with the second beverage
between successive beverage measurements.

Data Table C – Density of Reference Solutions

Beverage Mass, g Sample Volume, mL Density, g/mL
10.00
10.00
10.00

Calculations and Analysis

1. Plot density versus concentration for the five reference solutions on a graph. The concentration is the
independent variable (x-axis) and the density is the dependent variable (y-axis). Use a ruler to draw the

“best-fit” straight line through the data points.

2. Use the graph to estimate the unknown sugar concentration in the first beverage. To do this, locate the
point on the y-axis that corresponds to the density value of the beverage. Follow that point on the y-axis

across horizontally to where it meets the “best-fit” straight line through the data. Now read down
vertically from this point on the “best-fit” line to the x-axis. The point where this vertical “line” meets

the x-axis equals the percent concentration of sugar in the beverage solution. Construct a Results Table
and record the density of the beverage and the estimated percent sugar concentration.

3. Repeat step 2 to determine the percent sugar concentration of your beverages. Record all information in
your results table.

64

4. Calculate the actual or accepted value of the sugar concentration in weight percent for each beverage,
using the nutrition label information and the measured density value. Hint: See Pre-Lab Question #2 for

how to do this calculation. Record both the nutrition label information and the actual percent sugar
concentration in your results table.

5. Use the following equation, %   =   !"#$%&"'  !"#$%!!""#$%#&  !"#$% ×100% , to calculate the percent
!""#$%#&  !"#$%

error in your experimental determination of the sugar content in each beverage. Enter the percent error

in the results table. The measured value is the one you got on the graph and the accepted value is the one

you calculated in #4 above.

6. This lab looks at the relationship between the density of a beverage and its sugar content. What

assumption is made concerning the other ingredients in the beverage and their effect on the density of
the solution? Do you think this is a valid assumption? Explain.

7. When plotting data such as that obtained in this experiment, why is it not appropriate to “connect the

dots?” If you were to repeat the lab, do you think you would get exactly the same results? Comment on
the sources of error in this experiment and their likely effect on the results.

Results Table

Beverage Measured Percent Sugar Amount of Sugar Percent Sugar Percent Error
(from label)
density (g/mL) (Measured) (Label (g/total g))


 

65

Unit
 Test
 Setup
 

• 10 matching from ch. 2, 10 from ch. 9
• 10 multiple choice from ch. 2 and 10 from ch. 9

Short Answer – Complete any two. (5 pts. each)

Classify the following as a physical or chemical change.
sugar dissolves in water, molten wax turns to solid wax, charcoal burns in a grill, bread dough rises, copper wire is bent

When 400 g of wood burns, 30 g of ash remain. What happened to the remaining 370 g of matter?

Write the formula or name of the following compounds.

Name Formula

KBr

Na3PO4

sodium nitrate

boron trichloride

CF4

Classify the following compounds as either binary ionic, binary molecular, or ionic with polyatomic ions.

Name Classification

calcium oxide

nitrogen monoxide

oxygen difluoride

sodium chlorate

sodium hydroxide

Essay – Complete any two. (5 pts. each) - Number the essays you choose, and answer in the box.

Distinguish between the naming method of an ionic compound and a molecular compound. Use an example of each.

Explain the difference between a chemical change and a physical change and give an example of each.

Explain the difference between a homogeneous and heterogeneous mixture. Give an example of each.

The name a student gives for the molecular compound SiCl4 is monosilicon trichloride. Is this name correct? Explain
your answer.


 

66

Unit
 Review
 Materials
 

Chapter
 2
 Vocabulary
 Review
 

Each clue describes a vocabulary term. Read the clues and write the letters of each term on the lines provided.
1. Clue: part of a system having uniform composition and properties.

____ ____ ____ ____ ____

2. Clue: one- or two-letter designation for an element. (2 words)

____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____

3. Clue: another name for a homogeneous mixture.

____ ____ ____ ____ ____ ____ ____ ____

4. Clue: simplest form of matter that has a unique set of properties.

____ ____ ____ ____ ____ ____ ____

5. Clue: the amount of matter an object contains.

____ ____ ____ ____

6. Clue: matter that has a definite shape and volume.

____ ____ ____ ____ ____

7. Clue: a physical blend of two or more components.

____ ____ ____ ____ ____ ____ ____

8. Clue: matter that takes both the shape and volume of its container.

____ ____ ____

Write the letters found inside the circles on the lines below. Then unscramble them to find the term that describes matter that has a

uniform and definite composition. Scrambled letters ____ ____ ____ ____ ____ ____ ____ _____ _____
Solution: ____ ____ ____ ____ ____ ____ ____ _____ _____


 

67

Chapter
 9
 Vocabulary
 Review
 

Match the correct vocabulary term to each numbered statement. Write the letter of the correct term on the line.

Column A Column B

1. compounds that contain one or more hydrogen atoms and a. anion
produce hydrogen ions in solution

2. an ionic compound that produces hydroxide ions when b. law of multiple proportions
dissolved in water c. base
d. ionic compounds
3. any atom or group of atoms that has a positive charge e. binary compound

4. compounds composed of metal cations and nonmetal anions f. monatomic ion

5. composed of two elements and can be either ionic or
molecular

6. an ion consisting of a single atom with a positive or negative
charge

7. Whenever two elements form more than one compound, the g. cation
different masses of one element that combine with the same
mass of the other element are in the ratio of small whole
numbers.

8. a tightly bound group of atoms that behaves as a unit and h. polyatomic ion
carries a charge

9. In samples of any chemical compound, the masses of the i. acids
elements are always in the same proportions. j. law of definite proportions

10. any atom or group of atoms that has a negative charge


 
68

Unit
 Review
 –
 Chapters
 2
 and
 9
 
See p. 4
of notes

69

70