Physical Modeling in MATLAB Physical Modeling in MATLAB Physical Modeling in MATLAB
1DCHEM - PP#5 (Physical Properties) - …meant4teachers.com/.../2013/09/Physical-Properties.pdf ·...
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2/8/2013 1 SNC1D CHEMISTRY ATOMS, ELEMENTS, & COMPOUNDS L Physical Properties (P.148-151) Physical Properties All life on Earth depends on water. A characteristic of water is that it sticks to itself, a property known as cohesion. A physical property describes a characteristic of a substance that can be observed or measured. Another example of a physical property is the melting point of a substance. February 8, 2013 1DCHEM - Physical Properties 1 Physical Properties PHYSICAL PROPERTY characteristic of a substance that can be observed or measured February 8, 2013 1DCHEM - Physical Properties 2
Transcript of 1DCHEM - PP#5 (Physical Properties) - …meant4teachers.com/.../2013/09/Physical-Properties.pdf ·...
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SNC1DCHEMISTRY
ATOMS, ELEMENTS, & COMPOUNDS
L Physical Properties
(P.148-151)
Physical Properties
All life on Earth depends on water. Acharacteristic of water is that it sticksto itself, a property known ascohesion. A physical propertydescribes a characteristic of asubstance that can be observed ormeasured. Another example of aphysical property is the melting pointof a substance.
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Physical Properties
PHYSICAL PROPERTY
� characteristic of a substance thatcan be observed or measured
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Physical Properties
PRACTICE
1. Besides the melting point of a substance, what are some otherexamples of physical properties? List them.
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Physical Properties – Some Examples
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Physical Properties
PRACTICE
2. (a) What are some physical properties of sandpaper?
(b) Which of these physical properties make sandpaper useful?
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Physical Properties
PRACTICE
3. (a) What are some uses of duct tape?
(b) What physical properties of duct tape make it useful?
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Characteristic Physical Properties
If you had to identify a pure liquid, youcould perform various chemical tests onit. You could also examine the physicalproperties of the pure liquid. However,some physical properties are not usefulfor identifying a sample. Knowing thevolume and temperature of a mysterysample is not a great help becausethese values are not unique to thesubstance.
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Characteristic Physical Properties
Certain physical properties are unique to eachpure substance, like fingerprints are unique toeach person. These properties are calledcharacteristic physical properties, andthey can be used with confidence to identify apure substance. Unlike chemical tests,characteristic physical properties can bedetermined without changing the compositionof the sample, so the test sample isunchanged.
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Characteristic Physical Properties
PRACTICE
4. What are three common characteristicphysical properties?
• density
• freezing/melting point
• boiling point
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Characteristic Physical Properties
CHARACTERISTIC PHYSICAL PROPERTY
� physical property unique to a substance
� can be used to identify a substance
� three common physical properties are:
• density
• freezing/melting point
• boiling point
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Characteristic Physical Properties
PRACTICE
5. Explain why the boiling point of water is a characteristic physicalproperty, but the temperature of water is not.
the temperature is not unique or characteristic
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Characteristic Physical Properties
PRACTICE
6. What characteristic property of steel can be used to separate steelcans from aluminum cans at a recycling depot?
steel is attracted to a magnet but aluminum is not
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Characteristic Physical Properties
PRACTICE
7. Megan tested several properties of isopropyl alcohol, sometimes calledrubbing alcohol, in a lab investigation. She found that its volume was50 mL, its freezing point was -89EC, and it was colourless. Which of
these is a characteristic property?
freezing point and colour
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Characteristic Physical Properties – Density
As you may recall, density is the amount of matter per unit volume of thatmatter. The units of density are usually g/cm3 (solid) and g/mL (liquid).
DENSITY
where D is the density (g/cm3 or g/mL)
m is the mass (g) D=m/V m=DV V=m/D
V is the volume (cm3 or mL)
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m
D V
V
m D =
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Characteristic Physical Properties – Density
PRACTICE
8. A metal with a mass of 71.68 g occupies a volume of 8.00 cm3.Calculate the density of the metal. Be sure to show your work!
D = 8.96 g/cm3
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Characteristic Physical Properties – Density
PRACTICE
9. A sample of pure copper has a volume of 3.75 cm3. If the density ofpure copper is 8.96 g/cm3, calculate its mass . Be sure to show yourwork!
m = 33.6 g
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Characteristic Physical Properties – Density
PRACTICE
10. The density of liquid mercury is 13.53 g/cm3. The density of solidcopper is 8.96 g/cm3. Would you expect a piece of copper to sink orfloat when placed in a container of liquid mercury? Explain.
the copper would float when placed in the liquid mercury – this isbecause the density of copper is less than the density of liquid mercury(i.e. 8.96 < 13.53 g/cm3)
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Characteristic Physical Properties – Density
PRACTICE
11. Aluminum has a density of 2.7 g/cm3 while copper has a density of8.96 g/cm3. Which metal would you choose to build a model airplane?Why?
it would be better to build the model airplane using aluminum becauseit will be lighter in terms of density
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Characteristic Physical Properties – Density
PRACTICE
12. A drinking glass at a crime scene contains a clear colourless liquid thatmay be water or alcohol. As the investigator, you know that thedensities of alcohol, water, and ice are 0.79 g/mL, 1.0 g/mL, and 0.92g/mL. Design a simple method to determine the identity of themystery liquid. Explain your design.
place the ice cube in the liquid – if it floats that means the liquid mustbe water (0.92 < 1.0 g/mL) but if it sinks that means the liquid isalcohol (0.92 > 0.79 g/mL)
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Observing Physical Properties
We make direct observations when weare asked to determine the physicalproperties of a substance. For example,you might describe the substance on theright as white, odourless, and powdery.We make these observations using ourfive senses. Any property that does notprovide numerical information is called aqualitative property.
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Observing Physical Properties
QUALITATIVE PROPERTY
� property that is not measured (i.e. itdoes not have a value)
� observed using your 5 senses
� colour, odour, texture, …
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Observing Physical Properties
Further, we may take somemeasurements and note that thesubstance has a mass of 10.0 g and is ata temperature of 25EC. These measuredphysical properties give us numericalinformation about the substance. Thesetypes of information are quantitativeproperties of the substance.
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Observing Physical Properties
QUANTITATIVE PROPERTY
� property that is measured (i.e. it hasa value)
� temperature, height, mass, …
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Observing Physical Properties
PRACTICE
13. Uncooked spaghetti noodles are hard,brittle, and have an average length of26 cm.
(a) Which of these properties arequalitative?
(b) Which of these properties arequantitative?
(a) hard & brittle
(b) average length of 26 cm
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Observing Physical Properties
PRACTICE
14. A student recorded the following observations about a T-shirt. Classifyeach observation as a qualitative property or a quantitative property,and give reasons for your answers.
(a) It is red and grey in colour.
(b) It is 60 cm long.
(c) It is soft and stretchable.
(d) It will shrink in 70EC water.
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qualitative
quantitative
qualitative
quantitative
Physical Changes
If you take a piece of paper and fold it into a paper crane, does the paperundergo a chemical or physical change? It is true that the paper craneappears to be a new object, but the composition of the paper is notchanged. It is still paper, although with a different shape and size. Thischange is a physical change.
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Physical Changes
In a physical change, the composition ofthe substance remains exactly the same.No new substances are made. Forexample, boiling changes water from aliquid to a gas, but it does not changewater into a new substance. When waxis heated it melts but when it cools itturns back into a solid. Its physicalproperties changed, but its compositionstayed the same – the wax is still waxwhether it is solid or melted.
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Physical Changes
Dissolving is also a physical change. When salt isdissolved in water, you cannot see the salt, but ifyou took a sip you would taste the salt. And, ifyou allowed the water to evaporate, the saltwould remain in the container. Dissolving salt inwater does not produce a new substance. So, it isa physical change.
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Physical Changes
NOTE!
Some physical changes can be reversed. For example, when sugardissolves in water, the change can be reversed by evaporating the wateraway. Other physical changes cannot be reversed. For example, if youwere to cut a log into lumber, you could not put the log back together.
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Physical Changes
PHYSICAL CHANGE
� change in which the composition of the substance remains the same
� no new substances are produced
� generally easy to reverse (but not always)
� melting, boiling, dissolving, …
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Physical Changes
PRACTICE
14. Solids, liquids and gases are called states of matter. Specific terms areused to describe changes of state of a substance. Copy and completethe diagram showing the physical changes that water undergoes as itchanges states.
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Physical Changes
PRACTICE
15. In each of the situations below, it seems that a new substance mayhave been produced. Explain why each situation represents a physicalchange.
(a) A tailor makes a new suit out of a piece of fabric.
(b) A chef makes a salad out of lettuce, tomatoes, and cucumbers.
(c) A mechanic builds a boat engine out of a lawnmower.
(d) A chemist boils water until only salt crystals are left.
(e) A child makes juice by adding water to juice concentrate.
in each case the appearance has changed but the original materialhas not changed
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Activity: Vial Lab (1DCHEM-ASG#1)
INSTRUCTIONS
A. Read the activity “1DCHEM - ASG#1 (Vial Lab)”.
B. Follow the instructions given (i.e. method 1 to 5).
C. Answer the questions given (i.e. analysis 1 to 4).
D. Submit a formal lab report.
NOTE!
• This is a “practice” formal lab report. We will write up the lab togetherusing the QHMMOCA format so that you have an understanding ofwhat is required for a formal lab. You may find the “Lab ReportScheme” handout very useful.
• Formal lab reports are evaluated on a number of levels includingspelling and grammar, form, and content. Simply handing in a table ofobservations and the answers to the questions is not acceptable whena formal lab report has been requested!
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U Check Your Learning
TEXTBOOK
P.161 Q.8
WIKI (CHEMISTRY)
O.... 1DCHEM - WS#3 (How Do Scientists Measure Things)
O.... 1DCHEM - QUIZ#2 (Matter)
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