Physical Science Chapter 2: Matter

Mixtures can be physically separated. Describe an example of this.

- Separating salt water into its parts by heating it - Using a distillation device to heat a mixture whose components have different boiling points: The component that boils and evaporates first separates from the mixture - Using a centrifuge: The mixture spins rapidly until the mixture separates

Some compounds can be broken down through chemical changes. Describe an example of this.

- When mercury oxide is heated, it breaks down into elements mercury and oxygen - When a current is passed through melted table salt, the elements sodium and chlorine are produced - When you open a bottle of soda, carbonic acid in the soda breaks down into carbon dioxide and water

A substance has a mass of 360 g and a volume of 7.5 mL. What is its density?

48 g/mL

The chemical symbol for sulfuric acid is H2SO4. How many atoms are contained in each molecule of sulfuric acid?

7

What is an example of a gas-liquid mixture?

A carbonated drink

Describe a chemical change

A change that occurs when one or more substances change into entirely new substances with different properties.

What does a chemical property describe?

A chemical property describes how a substance changes into a new substance, either by combining with other elements or by breaking apart into new substances.

Elements combine chemically to form what?

A compound

Unlike a mixture, a pure substance has ____________________.

A fixed composition

What is a molecule?

A group of atoms that are held together by chemical forces.

What is a pure substance?

A sample of matter, either a single element or a single compound, that has definite chemical and physical properties.

Describe a compound.

A substance made up of atoms of two or more different elements joined by chemical bonds.

Describe an element

A substance that cannot be separated or broken down into simpler substance chemical means.

Give an example of an element

Bronze

Give some examples of chemical changes

Burning, rusting, digesting, decomposing

What are some signs that a chemical change has taken place?

Change of color, change of smell, fizzing, production of heat, production of sound, production of light

What are physical properties?

Characteristics that can be observed without changing the identity of a substance.

Digesting food is an example of

Chemical change

The chemical formula for a chlorine molecule, which contains two chlorine atoms, is ______________________.

Cl2

Which of the following is made of at least two different types of atoms?

Compound

What are some examples of physical changes?

Cutting, crushing, reshaping, changing shape

Describe density. How is it calculated?

Density is the ratio of the mass of a substance to the volume. The equation is Density = Mass/Volume It is a physical property.

Every sample of matter is what?

Either an element, a compound, or a mixture.

Name two chemical properties

Flammability: the ability to burn Reactivity: the capacity of a substance to combine chemically with another substance

Matter is defined as anything that ___________________________________.

Has mass and takes up space

What is matter?

Matter is anything that has mass and takes up space.

Describe the difference in how mixtures and compounds can be broken down.

Mixtures can be separated by physical changes, but compounds must be broken down by chemical means.

The smallest unit of a substance that behaves like a substance is a(n)

Molecule

Chemical formulas represent compounds. Give an example of a chemical formula.

One example is C3H6O, which is the chemical formula for Acetone.

How many atoms is a element made of?

One kind of atom.

The chemical symbol O stands for the element ____________________.

Oxygen

Which of the following is an example of a chemical change?

Paint fading

What is a physical change?

Physical change is a change of matter from one form to another without a change in chemical properties. Does not change the substance's identity

Chemical changes cannot be reversed by ________________________.

Physical changes

How can physical properties be useful?

Physical properties can be observed or measured without changing the composition of matter. They can be used to observe and describe matter.

How are physical and chemical properties different?

Physical properties can be observed without changing the identity of a substance, but chemical properties can be observed only in situations in which the identity of the substance changes.

Stainless steel has chemical properties such as

Resistance to rust

What are examples of physical properties?

Shape, color, texture, state, melting point, boiling point, strength, hardness, magnetism, ability to conduct heat or electricity

Define homogeneous mixture

Substances are evenly distributed, and the mixture is the same throughout.

Define a heterogeneous mixture

Substances aren't mixed uniformly and are not evenly distributed.

Define miscible

Substances that can be mixed.

Define immiscible

Substances that cannot be mixed.

What is an atom?

The smallest unit of an element that maintains the properties of that element.

Define boiling point

The temperature and pressure at which a liquid becomes a gas.

Define melting point

The temperature and pressure at which a solid becomes a liquid.

Define mixture

a combination of two or more pure substances that are NOT chemically combined.

What is the smallest unit of matter that can exist by itself and retain all of the substance's chemical properties?

an atom

The smallest unit of an element that behaves like an element is a(n)

atom

Which of the following is NOT an example of a physical property? a.) Freezing point b.) Reactivity c.) Density d.) Boiling point

b.) Reactivity

A group of atoms are held together by ________.

chemical forces

Ice floats in water because it is __________________ than water.

less dense

Two or more liquids that can dissolve into each other are referred to as _______________.

miscible

Wheat ground into flour is an example of a(n) ___ change.

physical

A molecule is the smallest unit of a substance that retains the ________________ of that substance.

properties

Tooth fillings are often made of gold or porcelain because those materials are NOT ____________________________.

reactive

Elements are represented by _______.

symbols