Chemistry is a Physical Science Chapter 1, Sections 1 and 2.
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Transcript of Chemistry is a Physical Science Chapter 1, Sections 1 and 2.
Chemistry is a Physical Science
Chapter 1, Sections 1 and 2
Introduction Chemistry: the study of the composition,
structure and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes
There are six branches of chemistry to deal with the main areas of study
The branches often overlap
Matter
Mass: a measure of the amount of matter Matter: anything that occupies space
(has volume) and has mass
Basic Building Blocks of Matter
• Atom: the smallest unit of an element that maintains the chemical identity of that element
• Element: a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom
More Building Blocks
Compound: a pure substance that can be broken down into simple stable substances
Each compound is made from the atoms of two or more elements that are chemically bonded
Molecule: smallest unit of an element or compound that retains all the properties of that element or compound (for now)
Types of Properties
• Extensive properties: depend on the amount of matter that is present
Examples include: volume, mass, amount of energy in a substance
• Intensive properties: do not depend on
the amount of matter present
Examples include: melting and boiling point, density, ability to conduct electricity and
transfer heat
Properties Physical properties: properties that can be
observed and measured without changing the material's composition
• Examples would be color, density, melting point, boiling point
Chemical properties: properties that can only be observed by changing the composition of the material
• Examples: reactivity, ability to burn, acidity, decompose
Changes
Chemical change: changes the chemical properties of the substance, you will have new substance(s) with new properties
A chemical change is the result of a chemical reaction
Physical change: does not change the chemical properties of the substance, usually changes its state of matter
Changes
• Reactants: the substances that react in a chemical change
• Products: the substances that are formed by the chemical change
States of Matter
• Solid: has a definite volume and definite shape
• Liquid: has a definite volume but an indefinite shape (assumes the shape of the container)
• Gas: no definite volume or shape (assumes the shape of the entire container)
• Plasma: high-temperature physical state of matter in which atoms lose most of their electrons
Mixture
Different substances not combined chemically
Can be separated by physical means Ratio of the components is not constant Its properties are similar to those of its
components
Types of Mixtures
• Homogeneous mixture
• uniform in composition
• AKA solution
• Heterogeneous mixture
• Not uniform throughout
• Can usually see the different components
To Separate a Mixture
Pick out the big pieces
Filtration, decant,
centrifuge Paper
chromatography Distillation Use of a magnet
Pure Substances
Can only be separated by chemical means All samples have identical chemical
properties with the same composition Are further divided into elements and
compounds Elements can not be split up into simpler
substances by chemical means, compounds can
HON and the Halogens
Hydrogen (H), oxygen (O), nitrogen (N), and the halogens (fluorine, chlorine, bromine, and iodine) are diatomic in all physical states