CHAPTER 1: INTRODUCTION TO

MATTER

1. DESCRIBING MATTER• MATTER: It’s anything

that has mass and takes up space.

• CHEMISTRY: the study of the properties of matter and how matter changes

• SUBSTANCE: It’s a single kind of matter that is pure. It has always a specific makeup

• Every form of matter has two kinds of properties: physical and chemical.

• PHYSICAL PROPERTIES: characteristic of a pure substance that can be observed without changing it into another substance.

• CHEMICAL PROPERTIES: characteristic of a pure substance that describes its ability to change into different substances.

ELEMENT:• It is a Pure substance

that cannot be broken down into any other by physical or chemical means. Simplest substance.

• ATOM: basic particle from which all elements are made. Element’s properties differ due to the difference in the atoms.

• CHEMICAL BOND: force of attraction between two atoms.

• MOLECULES: Combination of atoms into larger particles.

• COMPOUND: pure substance made of two or more elements chemically combined in a set ratio. They are represented by a chemical formula.–Ex: H2O, CO2, C6H12O6…

• When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements.

• MIXTURES: It’s made of two or more substances (elements, compounds of both)–Each substance in a

mixture keeps its individual properties.

–The parts of a mixture are not combined in a set ratio

– Heterogeneous Mixtures: you can see the different parts

– Homogeneous Mixtures: you can´t see the different parts• Liquids: solution (sea water)

• Solids: alloy of metals

• Gases: Air

2. MEASURING MATTER• WEIGHT: it is a measure

of the force of gravity on you. It is a force.

• MASS: it is the measurement of the amount of matter in the object.–Unit (SI): kilogram-

kg–1kg= 1000 g (grams)

Which property do scientists prefer to describe matter?Weight or mass?

• VOLUME: the amount of space that matter occupies.– Unit (SI): liter (l), mililiter

(ml) and cubic centimeter (cm3)

– 1 liter= 1000 ml– 1 ml= 1 cm3

– Calculate volume: • Volume= lenght x width x height

• Units= cm x cm x cm= cm3

How can you measure the volume of an irregular object?

Archimedes

• DENSITY: relates the mass of a material in a given volume

– Units (SI)= g/cm3

– Density of pure water is 1g/cm3.(4℃) Objects with greater density will sink, less will float.

volume

massdensity

Sample Problem A sample of liquid has a mass of 24g

and a volume of 16ml. What is the density of the liquid?

1.5g/ml

A piece of solid metal has a mass of 43.5g and a volume of 15cm3.What is the density of the metal?

2.9g/cm3

http://upload.wikimedia.org/wikipedia/commons/7/7a/Dead_sea_newspaper.jpg

3. CHANGES IN MATTER• A substance that undergoes

a physical change is still the same substance after the change.– Change in shape or form

(ex: sugar)• Common States of matter:

(on the earth)– Solid– Liquid– Gas

Other states (in the universe)

Plasma

Supersolid Neutronium

• A change in matter that produces one or more new substances is a chemical change or a chemical reaction.

• New substances with new properties are produced.– I.e.: combustion,

oxidation…

• Law of Conservation of Mass or Matter (Lavoisier-1770): matter is not created or destroyed, It is only transformed.

Energy is the ability to do work or cause change. Examples:bending a paper clip

Ice changing to liquid waterCandle wax burning, giving off energy

• Temperature is a measure of the average energy of random motion of particles of matter.

• (I.e.: Air-conditioned: particules of gas in the warm outside air have greater energy of motion than the ones in the cool building.)

• Thermal energy is the total energy of all the particles in an object. Not the same than temperature. Always flow from warmer to cooler.–Endothermic: energy

is taken (ice melting)–Exothermic: energy

is given off or released (combustion)

4. ENERGY AND MATTER• Forms of energy:

1.Kinetic: the energy of matter in motion.

2. Potential: the energy an object has because of its position.

3. Chemical: energy stored in the chemical bonds between atoms.

Energy

4. Electromagnetic: it travels to the space as waves (ex:radio, microwave…)

5. Electrical: the energy of electrically charged particles moving from one place to another.• Electrode: metal strips

placed in solutions, attached to a wire, connected to a battery.

Transforming Energy

• During a chemical change, chemical energy may be changed to other forms of energy. Other forms of energy may also be changed to chemical energy.