Chapter 5Chapter 5

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• Scientists used the term physical property to describe a characteristic of matter that you can detect with your senses.

• A physical property is any characteristic of matter that can be observed without changing the identity of the material.

Physical Properties

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• You probably are familiar with some physical properties, such as color, shape, smell, and taste.

• You might not be as familiar with others, such as, mass, volume, and density.

Common Physical Properties

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• Mass (m) is the amount of matter in an object. A golf ball has more mass than a table-tennis ball.

• Volume (V) is the amount of space that matter takes up. A swimming pool holds a larger volume of water than a paper cup does.

Common Physical Properties

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• Density (D) is the amount of mass in a given volume. A gold ball is more dense than a table-tennis ball. Density is determined by finding the mass of a sample of matter and dividing this mass by the volume of the sample.

Common Physical Properties

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• Bowling balls appear to be the same size, shape, and color, but do they all have the same mass?

Density

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• If you picked up these bowling balls, you would discover that their masses differ.

• The densities of the bowling balls are different because their masses are different.

• In some cases, density also can be used to identify unknown compounds and elements.

Identifying Unknown Substances

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• The element silver, for example, has a density of 10.5 g/cm3 at 20°C.

• You can find the ring's density by dividing the mass of the ring by its volume.

• State of matter is another physical property. State of Matter

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• The state of matter tells you whether a sample of matter is a solid, liquid, or a gas.

• This property depends on the temperature and pressure of the matter.

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• Some physical properties change when the size of an object changes. These properties are called size-dependant properties.

Size-Dependant and Size-Independent Properties

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• For example, a wooden block might have a volume of 30cm3. A larger block might have a volume of 60cm3. The volume of the block changes when the size of the block changes.

• Some physical properties do not change when an object changes size. Density is an example of a size-independent property.

Size-Dependant and Size-Independent Properties

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• The strength of an acid or base can be determined by finding the pH of the sample.

Physical Properties of Acids and Bases

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• The pH scale has a range of 0 to 14.

Physical Properties of Acids and Bases

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• Acids have a pH below 7.

• Bases have a pH above 7.

Physical Properties of Acids and Bases

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• A sample with a pH of exactly 7 is neutral— neither acidic nor basic.

• Some acids, such as concentrated hydrochloric acid, are dangerous.

Properties of Acids

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• But some acids are edible.

• Carbonated soft drinks contain acids.

Properties of Acids

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• Every time you eat a citrus fruit such as an orange or a grapefruit, you eat citric and ascorbic (uh SOR bihk) acids.

• The sharp smell of a freshly sliced lemon comes from the citric acid in the fruit.

Properties of Acids

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• Take a big bite out of the fruit and you will immediately notice a sour taste.

• If you then rubbed your molars back and forth, your teeth would squeak.

• All of these physical properties are common in acids.

• A familiar example of a base is soap.

Physical Properties of Bases

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• Soap has a slippery feel.

• You shouldn't taste soap, but if you accidentally did, you'd notice a bitter taste.

• A bitter taste and a slippery feel are physical properties of bases.

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Question 1

A tennis ball and a billiard ball may be the same size, but they will definitely not have the same _______.

A. densityB. parityC. viscosityD. wattage

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Answer

The answer is A. The billiard ball is much denser than the tennis ball.

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Question 2

Density is equivalent to mass divided by _______.

Answer

The answer is volume. The formula for determining density is D = m/V.

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Question 3

An example of a size-independent property is _______.

A. densityB. massC. volumeD. width

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AnswerThe answer is A. Other physical properties are shown in this table.