chemistry unit two test review

List four indicators that a chemical change has probably occurred.

1. Change in color 2. Change in odor and taste 3. Formation of precipitate 4. Formation of gases

chemical property

the ability or inability of a substance to combine with or change into one or more new substnaces

mass

the amount of matter the object contains

precision

the exactness of a measurement

Is the process of bananas ripening a chemical change or a physical change? Explain.

Chemical

At what temperature would 250 mL of water boil? 1000 mL? Is the boiling point an intensive or extensive property? Explain.

Always at 100°C no matter what its volume. Boiling point is an intensive property because it doesn't depend on the amount of substance present

"Properties are not affected by changes in temperature and pressure." Is this statement true or false? Explain.

False, the higher the temperature, the higher the pressure

"A mixture is the chemical bonding of two or more substances in any proportion." Is this statement true or false? Explain.

False, you can separate the substances.

Seawater is composed of salt, sand, and water. Is seawater a heterogeneous mixture or a homogeneous mixture? Explain.

Heterogeneous due to the presence of sand

physical property

a characteristic of matter that can be observed or measured without changing the sample's composition - for example, density, color, taste, hardness, and melting point

compound

a chemical combination of two or more different elements; can be broken down into simpler substances by chemical means and has properties different from those of its component elements

gas

a form of matter that flows to conform to the shape of its container, fills the container's entire volume, and is easily compressed

liquid

a form of matter that flows, has constant volume, and takes the shape of its container

solid

a form of matter that has its own definite shape and volume, is incompressible, and expands only slightly when heated

solution

a homogeneous mixture of two or more substances

mixture

a physical blend of two or more pure substances in any proportion in which each substance retains its individual properties; can be separated by physical means

intensive property

a physical property that remains the same no matter how much of a substance is present

extensive property

a physical property, such as mass, length and volume and is dependent on the amount of substance present

element

a pure substance that cannot be broken down into simpler substances by physical or chemical means

Describe a method that could be used to separate each mixture. a. iron filings and sand b. sand and salt c. the components of ink d. helium and oxygen gases

a. A magnet b. Filtration c. Chromatography d. Distillation

Identify each physical property as extensive or intensive. a. melting point b. mass c. density d. length

a. Intensive b. Extensive c. Intensive d. Extensive

Classify each as either a solid, a liquid, or a gas at room temperature. a. milk b. air c. copper d. helium e. diamond f. candle wax

a. Liquid b. Gas c. Solid d. Gas e. Solid f. Solid

Classify each as a physical property or a chemical property. a. aluminum has a silvery color b. gold has a density of 19g/cm3 c. sodium ignites when dropped in water d. water boils at 100°C e. silver tarnishes f. mercury is a liquid at room temperature

a. Physical b. Phyiscal c. Chemical d. Physical e. Chemical f. Physical

Classify each as a physical change or a chemical change. a. breaking a pencil in two b. water freezing and forming ice c. frying an egg d. burning wood e. leaves changing colors in the fall

a. Physical b. Physical c. Chemical d. Chemical e. Chemical

Which of the following are the same and which are different? a. a substance and a pure substance b. a heterogeneous mixture and a mixture c. a substance and a mixture d. a homogeneous mixture and a solution

a. Same b. Different c. Different d. Same

substance

anything that contains one type of matter

matter

anything that has mass and takes up space

qualitative

data in the form of words

quantitative

data that is in numbers

accuracy

how close a measurement is to the true value

heterogeneous mixture

one that does not have a uniform composition and in which the individual substances remain the same

homogeneous mixture

one that has a uniform composition throughout and always has a single phase; also called a solution