Chemistry- Chapter Three Course Objective Book Questions

What is a mixture?

A mixture is composed of two or more pure substances that have been mixed together in a variable proportion.

Classify each property as physical or chemical. The tendency of silver to tarnish The shine of chrome The color of gold The flammability of propane gas

Chemical Physical Physical Chemical

Classify each mixture as homogeneous or heterogeneous. Baby oil Chocolate chip cookie water and gasoline wine

Homogeneous Heterogeneous Heterogeneous Homogeneous

Classify each mixture as homogeneous or heterogeneous. Coffee Chocolate Sundae Apple Juice Gasoline

Homogeneous Heterogeneous Homogeneous Homogeneous

What is the difference between a crystalline solid and an amorphous solid.

A crystalline solid has atoms arranged in a repeating geometric pattern, whereas an amorphous solid has atoms that do not form repeating patterns.

What are the properties of a gas?

A gas has not fixed volume or shape. Rather, it assumes both the shape and the volume of the container it occupies.

What is the difference between a homogeneous mixture and a heterogeneous mixture?

A heterogeneous mixture has two or more distinct regions that have different compositions. A homogenous mixture has only one region and the composition of the mixture does not change.

What are the properties of a liquid?

A liquid has a fixed volume, but will assume the shape of the container it fills. Like solids, liquids are not compressible.

What is the difference between a mixture and a compound?

A mixture is formed when two or more pure substances are mixed together, but a new substance is not formed. A compound is formed when two or more elements are bonded together in a fixed ratio to form a new substance.

What is the difference between a physical change and a chemical change?

A physical change is one that does not alter the chemical composition of a compound. A chemical change, however, will alter the chemical composition of a compound.

What is the definition of a physical property? What is the definition of a chemical property?

A property of a substance that can be determined or observed without changing the chemical composition is called a physical property. A property in which the chemical composition of a substance is altered is called a chemical property.

What is a pure substance?

A pure substance is composed of only one type of atomor one type of molecule.

What are the properties of a solid?

A solid has a fixed volume and a definite shape, and is not compressible.

A block of aluminum is (A) ground into aluminum powder and then (B) ignited. It then emits flames and smoke. Classify (A) and (B) as chemical or physical changes.

A) Physical B) Chemical

Several pieces of graphite from a mechanical pencil are (A) broken into tiny pieces. Then the pile of graphite is (B) ignited with a hot flame. Classify (A) and (B) as chemical or physical changes.

A) Physical B) Chemical

What is an element? A compound?

An element is a substance that cannot be broken down into two or more simpler substances. A compound is a substance that is made up of two or more elements in a fixed ratio. A compound can be broken down into simpler substances (the atoms that make up the compound).

What is an endothermic reaction? Which has greater energy in an endothermic reaction, the reactants or the products?

An endothermic reaction is a chemical reaction that absorbs energy. The products have greater energy than the reactants.

What is an exothermic reaction? Which has greater energy in an exothermic reaction, the reactants or the products?

An exothermic reaction is a chemical reaction that releases energy. The reactants have greater energy than the products.

Determine whether each change is physical or chemical. A balloon filled with hydrogen gas explodes upon contact with spark. The liquid propane in a barbeque evaporates away because the user left the valve open. The liquid propane in a barbeque ignites upon contact with a spark. Copper metal turns green on exposure to air and water.

Chemical Physical Chemical Chemical

What is chemical energy? List some examples of common substances that contain chemical energy.

Chemical energy is a form of potential energy associated with the position of particles that compose the chemical system. Examples of chemical energy are the burning of gasoline and the burning of natural gas that can move objects or provide heat.

How do the three temperature scales differ?

Differ in the size of a degree and in how they define zero. The Kelvin, or absolute temperature scale, defines absolute zero as the temperature at which all atomic and molecular motion ceases. There can be no temperature lower than this. Celsius defines zero as the temperature at which water freezes as zero and the boiling point of water is 100 degrees C. On the Fahrenheit scale, water freezes at 32 degrees F and boils at 212 degrees F. The size of a 1 degree change in the Celsius and Kelvin scales is the same, whereas a change of 1 degree in the Celsius scale equals a 1.8 degree F change.

Classify each pure substance as an element or a compound. Carbon Baking soda (sodium bicarbonate) Nickel Gold

Element Compound Element Element

Classify each pure substance as an element or a compound. Aluminum Sulfur Methane Acetone

Element Element Compound Compound

What is the definition of energy?

Energy is the capacity to do work or generate heat.

Why are gases compressible?

Gases are compressible because there is a large distance, which can be decreased, between gas particles. Solids and liquids cannot be compressed because the particles that make them up are touching.

Explain the difference between kinetic energy and potential energy?

Kinetic energy is the energy associated with motion. Potential energy is the energy associated with position or composition.

What are the three states of matter?

Matter can be found as either solid, liquid or a gas.

Define matter and list some examples.

Matter is defined as anything that occupies space and has mass. It can be thought of as the physical material that makes up the universe. Examples are steel, wood, water and plastic.

What is matter composed of?

Matter is ultimately composed of tiny particles called atoms. Atoms are commonly found bonded to other atoms to form larger particles called molecules.

Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous. Urine Pure water Snickers bar Soil

Mixture, homogeneous Pure, compound Mixture, heterogeneous Mixture, heterogeneous

Classify each property as physical or chemical. The boiling point of ethyl alcohol The temperature at which dry ice sublimes The flammability of ethyl alcohol The smell of perfume

Physical Physical Chemical Physical

Determine whether each change is physical or chemical. Sugar dissolves in hot water. Sugar burns in a pot. A metal surface becomes dull because of continued abrasion. A metal surface becomes dull on exposure to air.

Physical Chemical Physical Chemical

The following list contains several properties of ozone (a pollutant in the lower atmosphere but part of a protective shield against UV light in the upper atmosphere). Which are physical, and which are chemical?

Physical Properties: bluish color, pungent odor, gas at room temperature. Chemical Properties: very reactive, decomposes on exposure to ultraviolet light.

The following list contains several properties of ethylene (a ripening agent for bananas). Which are physical properties, and which are chemical? Colorless Odorless Flammable Gas at room temperature 1 L has a mass of 1.260 under standard conditions Mixes with acetone polymerizes to form polyethylene

Physical Properties: colorless, odorless, gas at room temperature, one liter has a mass of 1.260 under standard conditions, mixes with acetone. Chemical Properties: flammable, polymerizes to form polyethylene.

Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous. Helium gas Clean air Rocky road ice cream Concrete

Pure, element Mixture, homogeneous Mixture, heterogeneous Mixture, heterogeneous

What are three common units for energy?

The common unit for energy in the laboratory is the joule (J). Another commonly used unit of energy found in nutritional information is the calorie (cal) and the Calorie (Cal). Finally, another common unit of energy is the kilowatt-hour (kWh) which is how electricity is measured from utilities.

What is the law of conservation of energy?

The law of conservation of energy states, "Energy can neither be created nor destroyed."

What is the law of conservation of mass?

The law of conservation of mass states, "Matter is neither created or destroyed in a chemical reaction."