Physical vs. chemical properties and changes keyMrs.Meer
the senses and can be determinedFor example, color, shape, mass, length and A chemical property indicates how a substance reacts with something else.
The original substance is fundamentally changed n observing a chemical property.
For example, the abilitychemical property.
The iron has reaciron metal is changed.
It now nce with a different formula.
4Fe + 3OClassify the following properties as either chemicalcolumn.Chemical1.blue color X
5.reacts with acid to form H
X 6.supports combustion
X 7.volume X
8.melting point X
reacts with water to form a gas
X 10.reacts with a base to form water
12.boiling point X
13.can neutralize a base
physical chemical chemical chemical chemical chemical chemical chemical chemical chemical anged in form.
In a chemical change, a new substance is produced.
Energy changes always accompany chemical changes.occurred):
energy change color change gas released (sometimes with an odor) precipitate formed (a precipitate is a solid formed during the reaction of two aqueous solutions) a physical or chemical change. hydroxide dissolves in water.potassium hydroxide to produce a salt, pellet of sodium is sliced in two.
is heated and changed into steam. chlorate decomposes to form solid potassium chloride and place in HO, a piece of sodium catches on fire as hydrogen gas is
hydroxide forms. melting. rotting. is digested in the stomach. is absorbed by a paper towel. freezing into ice.physical.
Section 2 physical propertiesSection 2 Physical Properties
Key Concept Physical properties of matter can be observed or
What You Will Learn Examples of physical properties are melting temperature, density, hardness, thermal conductivity, and electrical conductivity. Density is the amount of matter in a given space or volume. A physical change does not change the identity of the matter that undergoes the change. Melting, freezing, cutting, bending, and dissolving are physical changes.
Why It Matters Understanding the physical properties of matter can help you understand the physical changes that you observe in the matter around you.
Have you ever played the game called 20 Questions? The goal of this game is to figure out what object a person is thinking of by asking him or her no more than 20 yes-or-no questions.
What should you ask about? You may want to ask about the physical properties of the object.Knowing about the physical properties of an object can help you identify the object.
Identifying Physical Properties The questions in Figure 1 ask about four characteristics of an object: color, odor, mass, and volume.These characteristics are physical properties of matter.A physical property of matter is a characteristic Figure 2 shows six physical properties.
Figure 1 Asking questions about the physical properties of an object can help you identify it.Other physical propertiessuch as magnetism, electrical conductivity, strength, and flexibilitycan help you identify ways to use a substance.
Think of a scooter that has an electric motor.The magnetism produced by the motor is used to convert energy store
List four physical properties.
Figure 2 Examples of Physical Properties
Density Density is a physical property that describes the relationship between mass and volume.Density is the amount of matter in a given space or volume.A golf ball and a table-tennis ball have similar volumes, as Figure 3 shows.
But a golf ball has more mass than a table-tennis ball does.So, the golf ball has a greater density than the table-tennis ball does.
Figure 3 A golf ball is denser than a table-tennis ball because the golf ball contains more matter in a similar volume.D), first measure its mass (m) and volume (V).
Then, use the equation below.
Units for density consist of a mass unit divided by a volume unit.
The density units most often used are grams per cubic centimeter (g/cm3) for solids and grams per milliliter (g/mL) for liquids.The density of a given substance remains the same no matter how much of the substance you have.That is, the density of 1 cm3 of a substance is equal to the density of 1 km3 of that substance.
What is density, and how do you calculate it?
Using Density to Identify Substances Density is a useful physical property for identifying substances.At a given temperature and pressure, a substance maintains a constant density.
Table 1 shows the densities of several substances.
Table 1 Densities of Common Substances* Substance Density* (g/cm3) Substance Density* (g/cm3) Helium (gas) 0.0001663 Zinc (solid) 7.13 Oxygen (gas) 0.001331 Silver (solid) 10.50 Water (liquid) 1.00 Lead (solid) 11.35 Pyrite 5.02 Mercury 13.55
*at 20C and 1
Section 2 Physical Properties - Midway Middle School Science - …
• Examples of physical properties are melting temperature, density, hardness, thermal conductivity, and electrical conductivity. (mtlsd.org)
Chapter Physical Properties Section - Omsd Home Page
Examples of physical properties include color, odor, texture, and shape. How would you identify a fruit as an apple? You would probably first look (midwaymsscience.weebly.com)
Eens 2110 Mineralogy Tulane University Prof. Stephen A. Nelson ...
Physical Properties of Minerals ... examples, see figure 5.6 on page 120of your text. Physical Properties of Minerals Page 2 of 8 9/26/2011. Parting (omsd.omsd.k12.ca.us)
Density of Solids Which would you rather carry around all day: 1 kg of lead or 1 kg of feathers? They have the same mass, so their masses do not make one easier to carry than the other.But lead is denser than feathers.A kilogram of lead has a volume smaller than a stick of butter.A kilogram of feathers has the volume of a bed pillow.
This difference in volume makes the lead less awkward to carry than the feathers.
Density, Floating, and Sinking Knowing the density of a substance can tell you if the substance will float or sink in water.
If the density of an object is less than the density of water, the object will float.Cork, most woods, and some plastics are less dense than water.
So, they float in water.On the other hand, an object whose density is greater than the density of water will sink in water.Most rocks and metals are denser than water.
So, they sink.
How can you use density to predict whether an object will float or sink?
Liquid Layers What do you think causes the liquids in Figure 4 to look the way they do in the graduated cylinder? Does trick photography make them look that way? No, differences in density do! Six liquids are in the graduated cylinder.Each liquid has a different density.If the liquids are carefully poured into the cylinder, they form six layers because of the differences in density.The densest layer is on the bottom.The least dense layer is on the top.The order of one another.
Figure 4 This graduated cylinder contains six liquids that form six layers because of the densities of the liquids.
The layers are in order of increasing density from the top to the bottom.
Physical Changes: No New Substances A change that affects one or more physical properties of a substance is a physical change.Imagine that a piece of silver is pounded and made into a heart-shaped charm.This change is a physical one because only the shape of the silver has changed.The piece of silver is still silver.
The identity of the substance is the same.Figure 5 shows more examples of physical changes.
Figure 5 Examples of Physical Changes
How are a substance and its physical properties affected during a physical change?
Examples of Physical Changes Water freezing to become ice cubes and a piece of wood changing shape as a result of being sanded are examples of physical changes.Such changes do not change the identities of the substances.Ice is still water.And sawdust is still wood.Also, an interesting physical change takes place when one substance dissolves in another substance.For example, when sugar dissolves in water, the sugar seems
Pages 46 51CHAPTER Properties of Matter Physical PropertiesBEFORE YOU READ8.7.c, 8.8.a, 8.8.b, 8.8.dSTUDY TIPIncrease Vocabulary this section silently.Underline READING CHECKCopyright
by Holt, Rinehart and Winston.All rights reserved.Properties of MatterSECTION 2Name Class DatePhysical Properties USING DENSITY TO IDENTIFY SUBSTANCESDensity is a useful physical property.At the same the table below.Helium (gas)0.000166Zinc (solid) 7.13Oxygen (gas)0.00133Silver (solid)10.5Water (liquid)1.00Lead (solid)11.4Pyrite (solid)5.02Mercury (liquid)13.5DENSITY OF SOLIDSWould you rather carry around 1 kg of lead or 1 kg of lead has about the same volume as a stick of butter.
A 1 as a pillow.The difference in volume makes the lead eas-ier to carry.DENSITY, FLOATING, AND SINKINGobject is less than the density of water, the object will float in water.Cork, many types of wood, and some plas-tics are less dense than water.
That is why they float in it.water, it will sink in water.Rock and many types of metal are denser than water, so they sink.
of regular soda in a tank of water.You can see that their Regular sodaDiet sodaIn a tank of water, a can of diet soda
oats, and a can of regular soda sinks.READING CHECKTAKE A LOOK 7.You are given an .Which READING CHECKWhen will an Critical ThinkingWhich Copyright
by Holt, Rinehart and Winston.All rights reserved.Properties of MatterSECTION 2Name Class DatePhysical Properties EXAMPLES OF PHYSICAL CHANGESthree states of matter.
Any change in state is a physical water.However, if the water evaporates, the sugar reappears, REVERSIBILITY OF PHYSICAL CHANGESbear-shaped mold.
When it cools, the gold becomes solid again, and a bear-shaped charm is formed.The gold goes MATTER AND PHYSICAL CHANGESPhysical changes do not change the identity of matter.change.Physical changes can often be reversed easily, READING CHECK13.
When a liquid READING CHECK14.What change or
gure may help you with the answer.READING CHECK15.What happens Copyright
by Holt, Rinehart and Winston.All rights reserved.Properties of MatterName Class DateSection 2 Review 8.7.c, 8.8.a, 8.8.b, 8.8.dSECTION VOCABULARYpropertiesphysical property as density, color, or hardness 1.Describe In words, explain how to calculate the density of a substance.SubstanceDensity (g/cmWood (oak) 0.85Water 1.00Ice cube 0.93Aluminum 2.7Lead11.3Gold19.3Ethanol 0.94Methanol 0.79 2.
Identify Will any of the other substances in the table float in methanol? Why?
3.Identify Which substance would have a mass of 135 g when it has a volume of
Identify Two balls have the same mass, but one has a larger volume than the other.
Which ball has the larger density?
5.Explain Most substances become more dense when they freeze.However, when.
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