Introduction to Chemistry Chapter 1 Introduction to Chemistry

1.2 Chemistry and Matter Chemistry is the study of matter and the changes that it undergoes Matter- anything that has mass and takes up space. Examples of matter: metal, plastic, paper, ink, etc. Not everything is matter, examples: heat, light, radio waves, knowledge, etc.

Mass vs. Weight Mass- measurement of the amount of matter Weight- measure of mater and the effect of gravitational pull Weight is not consistent, depends on gravitational pull Mass is consistent, not dependent of gravity

Branches of Chemistry Organic- carbon chemicals (Pharmaceuticals) Inorganic- no carbon chemicals (Metals, Minerals) Physical- behavior/changes of matter (Reaction Rates) Analytical- Compositions of substances (Food nutrients) Biochemistry- processes of living organisms (Metabolism)

1.3 Scientific Method Scientific Method- a organized process used by scientists to do research Observation- the act of gathering information Qualitative data- information using five senses (color, odor, shape) Quantitative data- numerical information (measuring, volume, pressure)

Practice Problem: Indentify each of the following as an example of qualitative data or quantitative data. Taste of an apple Mass of a brick Speed of a car Length of a rod Texture of a leaf Weight of an elephant

Scientific Method (Continue) Hypothesis- tentative explanation for what has been observed (testable statement) Experiments- set of controlled observations that test the hypothesis

Scientific Method (Continue) Variable- quantity or condition that can have more than one value Independent variable- that one you plan to change (Condition that affects the experiment outcome) Dependent variable- change in response to the independent variable

Practice Problems: Identify the dependent variable and the independent variable A student tests the ability of a given chemical to dissolve in water at three different temperatures. A farmer compares how his crops grow with and without phosphorous fertilizers. An environmentalist tests the acidity of water samples at five different distances from a factory.

Constant- factor(s) not allowed to change during an experiment Control- standard for comparison Conclusion- judgment based on the information obtained (A hypothesis can never be proven) Theory- explanation supported by many, many experiments (broad principle of nature) Scientific Law- a relationship in nature supported by many experiments

1.4 Scientific Research Pure research- seek to gain knowledge for the sake of knowledge itself Applied research- done to solve a specific problem Chance discoveries occur when the expected outcome is different and a new discovery is found (ex. Nylon)

Practice Problem Classify each kind of research as either pure or applied A scientist studies plants in a rain forest in search of chemicals that might be used to treat AIDS. A researcher studies the effect of hormones on the brain of a worm. A researcher tries to develop cleaner burning fuels to help reduce air pollutions.

Benefits of Chemistry Technological applications are a result of pure and applied research Technology- practical use of scientific information Technology’s purpose is to make improvements in human life (make life easier and more comfortable)