St. Augustine Preparatory School 2015/2016 Chemistry Chapter 1 St. Augustine Preparatory School 2015/2016

What is chemistry? Chemistry is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany the processes

There are numerous fields of chemistry Organic chem: study of carbon containing compounds Inorganic chem: study of non-carbon containing (non-organic) compounds Physical chem: the study of properties and changes of matter and their relation to energy Analytical chem: identification of the components and composition of materials

There are numerous fields of chemistry Biochemistry: study of processes and substances occurring in living things Theoretical chem: Using mathematics and computers to understand the principals behind observed chemical behaviours

Research Basic research – common knowledge Applied research – solving specific problems Technological Development – usually slower moving and further behind the research

Mass vs. Matter Mass is a measure of the amount of matter So then matter could be defined as:

Mass vs. Matter Mass is a measure of the amount of matter So then matter could be defined as: Anything that has mass and takes up space

Atoms Atoms are the smallest unit of an element that maintains the chemical identity of that element.

Elements Elements are pure substances that cannot be broken down into simpler, stable substances and is made of only one type of atom Many elements are diatomic, meaning they exist in pairs of two (HOFBrINCl or the “7 that make a 7”) Elemental phosphorous is found in groups of four Elemental sulfur is found in groups of eight

Substances have characteristic properties Extensive Properties: depend on the amount of matter that is present. (Volume, mass, and the amount of energy) Intensive properties: do not depend on the amount of matter (Boiling point, melting point, ability to conduct electricity)

There are also physical and chemical properties Physical properties: a characteristic that can be observed or measured without changing the identity of the substance Boiling point Melting point Density Color Lustre

Physical Change Any change that does not alter the identity of the substance

Changes to the states of matter are Physical Changes In groups of 3, you will read about solids, liquids, and gases on page 8 and 9 of your textbook Each individual in your group is responsible for reading one section and then explaining to their group what was mentioned in his/her section **Pay close attention to whether your state has a definite volume or takes the shape of a container**

Chemical Changes When chemical changes occur, the actual composition of the chemical is changed and new substances are formed Some signs of a chemical change (there are lots more): Color change Bubbling (from gas) in a reaction Formation of a solid (precipitate) Light is emitted

Are the following physical or chemical changes? A hot glass shatters when put into cold water Wood is burned in a fireplace A nail in a piece of wood rusting Tearing a piece of paper in half Food molding Perfume evaporating off of your skin Butter melting 8) Moth balls vaporizing in a closet

Matter can be a pure substance or a mixture Read pages 11, 12, and 13 on mixtures and pure substances. At the end, you should be able to sort different substances into: Mixtures or Pure substances Compounds, Elements, Heterogeneous mixtures, and Homogeneous mixtures *Try to think of an everyday example of each of the above categories