Chapter 1- What is Chemistry?

Pure substance

A single type of matter.

Is the air we breathe an elemental substance?

Yes.

Vaporization

Change from liquid to a vapor state (boiling water)

How many known elements are there?

118.

Matter

Anything that has mass and occupies space.

Give an example of a chemical property:

Flammability (also reactivity).

What type of mixture is a rock?

Heterogenous (different minerals).

What are the subdivisions of mixtures?

Homogenous and heterogenous.

What type of mixture is a cup of tea with sugar stirred in?

Homogenous.

Chemical formula

Indicates the number of atoms of each element that make up the smallest possible piece of that compound. H20 (chemical formula for water) tells us that the smallest possible piece of water is made from 2 hydrogen atoms and 1 oxygen atom.

What do physical properties of a pure substance characterize?

Its physical state and physical behavior.

Freezing

Liquid to a solid

Elemental substance

Made up of atoms of just one element. Example: a piece of pure gold.

The divisions and subdivisions of matter:

Matter --> pure substances (--> elemental substances + compounds) and mixtures (--> homogenous mixtures and heterogenous mixtures).

Physical transformation of a pure substance

One that leaves it as the same substance but in a different physical state (melting a Dairy Milk chocolate bar).

Compounds

Pure substances (single type of matter) made from atoms of two or more different elements. Example: water is a compound made from atoms of hydrogen and oxygen.

Atom

Smallest possible piece of an element.

Melting

Solid to a liquid

What are the three most common states of matter?

Solid, liquid, and gas.

What is another name for a homogenous mixture?

Solution.

What happens when you combine chlorine gas with sodium?

Table salt.

Technology

The application of science.

Elements

The basic building blocks of matter.

Science

The experimental investigation and explanation of natural phenomena. It is knowledge from experience.

Chemistry

The study of matter and the transformations it undergoes.

Condensation

Vapor to liquid (breathing on a window)

Sublimation

When a pure substance goes directly from the solid state to the gas state without passing through the liquid state. Solid carbon dioxide- dry ice.

Mixtures

When two or more pure substances are intermingled with each other.

Is air matter? Why?

Yes. It occupies space- the volume of a room. And a tank filled with air weighs more than a tank without air.

Classify a) a glass of water b) powdered lemonade c) lemonade from freshly squeezed lemons

a) water is a pure substance and a compound b) powdered lemonade is a homogenous mixture c) freshly squeezed lemonade is a heterogenous mixture as there is pulp present