Physical and Chemical Properties Worksheet

Physical and Chemical PropertiesName:_______________________________
Date:__________
This is a “do at home” lab. Submit the ENTIRE report, including completed
pre-lab, data and post lab, with photos embedded via canvas on the published
due date. Portions of this will take 3 days. Start early!
Objectives
In this lab exercise our objectives are
a) To observe the physical and chemical properties of several substances.
b) To determine the difference between chemical and physical properties
c) To determine and classify changes in matter as either chemical or physical
Introduction
Chemistry is the central science that seeks to understand matter by examining the composition,
structure, properties and interaction of matter. A good understanding of matter requires an
understanding of the physical and chemical characteristics or properties of matter and the
changes they can undergo. Such properties like color of a flower, the taste of an orange are
familiar to you. Physical and chemical changes are part of your everyday experience as well, for
example acidity of an orange. However, you may not yet have a clear idea of the difference
between a physical change and a chemical change. You may not yet know exactly how a
chemical change is distinguished from a physical change. The purpose of this experiment is to
clarify these important distinctions.
The physical properties of a substance are those properties that can be observed and measured
without changing the composition of the substance. Physical properties include odor, color,
density, solubility, boiling point, and melting point. Physical properties depend on there being
no change in composition, and hence some physical properties can be used to describe and
identify substances. Such physical properties are known as intensive properties. Here’s a good
example: A colorless, odorless liquid that freezes at 0°C is likely to be water.
The chemical properties of a substance are those properties that can only be observed
when the substance is subjected to an interaction with another substance or energy source. Then
the substance undergoes a change in composition. The fact that iron oxidizes in moist air to
produce the reddish-brown compound iron (II) oxide (rust!) is an example of a chemical
property. Chemical properties include oxidizing ability, reactivity, flammability and acidity.
In a physical change, only the temperature, size, or physical state of a sample of matter is
altered. The melting of ice and the evaporation of gasoline are examples of physical changes. In
chemical changes, new substances of different chemical composition are produced. Examples of
chemical change are the rusting of iron and the burning of wood. Readily observable phenomena
accompany chemical changes and are often telltale signs that such changes are taking place.
These indicative phenomena include the evolution of gas, the production of a color change, the
formation of a solid, the evolution of heat, temperature change (either hot or cold) and light
production. A process in which a chemical change takes place is called a chemical reaction. In
chemical changes, the original substances are consumed, and new substances are produced. The
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total mass of the products of the reaction will always be equal to the total mass of the reactants.
This result has been verified by countless experiments and is now accepted as a scientific law—
the law of conservation of mass.
In this experiment, you will examine a variety of substances and describe the physical
properties of each. You will then cause changes to take place in certain of the substances. Based
on your observations and the results of tests you will conduct, you will decide whether these
changes are physical or chemical in nature.
Materials and Equipment:
Containers – cups, glasses or bowls (preferably clear glass or plastic) of the same size,
Chocolate Chip Cookie (broken into 2 big pieces)
Slice of onion or a fruit of your choice
Ice (keep frozen and remove portions as needed)
sucrose (table sugar),
NaCl (granular table salt),
NaHCO3, plain baking soda,
iron nail (e.g. uncoated bright steal nail)
Milk
Soda (brown, e.g. Coca-cola)
HC2H3O2, Vinegar
C54H100O7, Vegetable oil
Pre-laboratory Assignment. (Submit your answers in the Pre-laboratory Quiz on Canvas)
1. What safety precautions must be taken in this experiment?
2. Give 3 experimental observations that indicate a chemical change has taken place. Do not list
chemical changes.
3. In your own words define the following:
a) pure substance
b) heterogeneous mixture
c) homogenous mixture
d) chemical property
e) physical change
f) intensive property
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Procedure, Results & Data Tables
Be sure to take pictures of setups and results.
1. Obtain cups or bowls and using a clean spoon, transfer a small amount of each substance listed in
Table PCP_1 into a separate container. Be sure you know what substance is in which container. Liquids
must be poured gently. Examine each substance carefully. Do not touch the substance with your hands.
Record all observations into data table PCP_1.
i.
Smell each item by wafting carefully to your nostrils. Indicate whether the item has an odor in the
second column below.
ii.
Describe the physical properties of your items in the third column.
iii.
Classify each of your substances as elements, compounds, or mixtures. If it is a mixture be sure
to state whether it is homogenous or heterogenous. Write your classifications in the fourth
column.
iv.
Test the solubility of each substance in water by adding a tablespoon of water to each in its
container. Record whether the solid substances dissolve and liquids mix completely in the fifth
column.
v.
Dispose of these mixtures appropriately and rinse/wipe your container dry. Solids that remain
may be saved for later use.
Table: PCP_1
Substance
Odor
Yes/No
Description, eg, color,
texture
Element/compound/
homogenous mixture/
heterogeneous mixture
Solubility in
water
Yes/No
ice
Coca-cola
Sucrose, table
sugar
NaCl, table salt
NaHCO3, baking
soda
Iron nail, Fe
Chocolate chip
cookie
Milk
Vinegar, HC2H3O2,
acetic acid
Vegetable oil,
C54H100O7
Slice of onion or a
fruit of your choice:
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2. Break the second half of the chocolate chip cookie into about 3 smaller pieces.
i.
ii.
iii.
iv.
v.
In a clean dry container, mix a small amount of salt, NaCl, with the broken pieces of chocolate
chip cookie.
Take a photo and record your observations in the first row of Table PCP_2 below.
Add one more teaspoon full of salt.
Take a photo and record your observations in the second row of PCP_2. Label and insert your
photos at the end of this document.
Determine whether the cookie and salt, is a homogeneous mixture, heterogeneous mixture, OR
compound. Record your answers in the second column.
Table: PCP_2
Substance
Observation
homogenous mixture/
heterogeneous mixture/compound
Cookie + NaCl
Cookie + 2x NaCl
1. Can you separate your product?
2. Why or why not?
3. How are mixtures different from compounds?
4. Conclusion:
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3a. Inspect the iron nail. Place the iron nail in a dry container and add a few drops of water to it.
i.
ii.
Place this outside in a place no one will disturb it and allow the nail and water to sit for three (3)
days. Each day, take a photo, record your observations into Table PCP_3a. Label and insert the
photos at the end of this assignment.
Classify your observation as a physical or chemical change.
3b. Place a chunk of ice into a dry plastic container and add a few drops of water to it.
i.
ii.
iii.
iv.
Allow the ice and water to sit at room temperature for a few minutes or up to 15 minutes.
Record your observations in Table PCP_3b.
Place the results in the plastic container into the freezer for 15 minutes.
Record your observations in Table PCP_3b. Classify your observation as physical or chemical
change.
Table: PCP_3a
Procedure
Observation
Is this Physical or
Chemical Change?
Evidence/reason for that
conclusion
Observation
Is this Physical or
Chemical Change?
Evidence/reason for that
conclusion
Nail + water
Day 1
Day 2
Day 3
Table: PCP_3b
Procedure
Ice + water
Room temperature
Freezer temperature
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4. Obtain 3 dry containers. Place a small amount (teaspoonful) of sucrose (table sugar) into container 1,
NaCl (table salt) into container 2 and NaHCO3 (plain baking soda) into container 3.
i.
Add two (2) tablespoonfuls of Acetic acid (Vinegar) to containers 1, 2 and 3. Take a photo as
soon as the vinegar is added. Label and insert your photos at the end of this document.
a. Be sure to watch what is happening in each container carefully.
ii.
Record your observations into Table PCP_4.
iii.
Classify your observation as a physical or chemical change.
Table: PCP_4
Procedure
Observation
Physical or Chemical
Change
Sucrose + acetic acid
NaCl + acetic acid
NaHCO3 + acetic
acid
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Name: ______________________________ Class/Section # _______ Date: _____________
Post Laboratory Assignment
(Submit your answers in the Post-Laboratory Quiz on Canvas)
This should take less than 10 minutes to complete
1. Classify the following aluminum-containing samples as an example of an element, compound,
homogenous or heterogeneous mixture.
a) bauxite, aluminum ore_____________________ b) aluminum, Al ____________
c) aluminum hydroxide , Al(OH)3______________ d) aluminum soda can__________
2. Give a physical and a chemical property for sodium metal.
Physical: _____________________________________________
Chemical: _____________________________________________
3. Determine whether the described property is an extensive or intensive property.
a) mass of a liquid: ________________
b) density of a liquid____________
c) melting point of zinc ____________
d) color of chlorine _______________
4. Classify the following changes as physical (phys) or chemical (chem)
a) Apple turns brown when it is cut.
________________
b) Sugar dissolves in water.
_________________
c) Sugar is caramelized (burned) during a cooking project.
________________
d) Bread is toasted.
_______________
e) A carton of dry ice, solid CO2, is opened and it disappears within an hour. _____________
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f) Silver jewelry turns green after being left outside for a week.
_______________
5. Give a hypothesis for the change of color of the iron metal as seen in table PCP_3a.
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