SECTION I: DEFINING MATTER. Chemistry is the study of the composition, structure and properties of...

SECTION I: DEFINING MATTER

Chemistry is the study of the composition, structure and properties of matter, the processes that matter undergoes and the energy changes that accompany these processes.

Matter is anything that has mass and volume.

Everything is made of matter

Characteristics used to describe an object

Properties are used to identify a substance

Ex: color, odor, shape, size, texture, hardness

Mass, weight, volume, and density

Mass is the amount of matter in an object

Mass is constant and does not change with location.

Mass is also the measure of inertia Inertia is the resistance of an object to changes in its

motion The more mass the greater the inertia

1kg = 1000g

1 lb = 454g

While mass deals with how much matter is present, weight takes into account the force of gravity.

Underwater and in space objects weight less than they do on earth but their mass is the same regardless of location.

Therefore, on Earth mass and weight represent the same thing.

Volume is the amount of space that an object occupies.

The volume of liquids are usually determined using a graduated cylinder.

Units of liquid volume: milliliter, liter, gallon, pint, etc.

1L = 1000mL

Volume of a regularly shaped solid is determined using a geometric formula

BOX: Volume = length X width X height

CYLINDER: Volume = ∏r2h

Units of solid volume: cm3

1mL = 1cm3

Volume of a dry powder can be measured using a graduated measuring cup.

Volume of an irregularly shaped object can be determined by immersing the object in water and measuring the amount of water displaced.

Extensive Properties-a characteristic that is specific to the amount of matter.

In other words, the property changes with the amount of the substance.

Ex. Mass, volume, weight, & length are extensive properties.

Extensive properties alone are not sufficient in identifying a substance.

Density- the amount of substance or mass contained in a certain space.

The mass per unit volume.Density is useful in identifying the composition of a substance.

Temperature alters the density of a substance

Density = mass/volume

Common Units of Density = g/mL, g/cm3

The density of water at room temperature is 1.0g/mL.

Any object with a density greater than 1.0g/mL will sink in water.

Any object with a density less than 1.0g/mL will float in water.

Material Density Material Density

Zinc 7.1g/cm3 Gold 19.3g/cm3

Paper 0.8g/cm3 Brass 8.4g/cm3

Water 1.0g/mL Copper 9.0g/cm3

Aluminum 2.7g/cm3 Lead 11.4g/cm3

Intensive Properties-a characteristic that does not depend on the size or amount of matter.

In other words, the property remains constant regardless of the amount of the substance.

Ex. Density, color, hardness, boiling point, melting point, etc.

Intensive properties are useful in identifying a substance.