CHEMISTRY 103 Fall 2017

Why Study Chemistry? Think about current issues in the news.

Why Study Chemistry? Think about current issues in the news. Energy sources

Why Study Chemistry? Think about current issues in the news. Energy sources Greenhouse effect

Why Study Chemistry? Think about current issues in the news. Energy sources Greenhouse effect Pollution

Why Study Chemistry? Think about current issues in the news. Energy sources Greenhouse effect Pollution Ozone problem

Why Study Chemistry? Think about current issues in the news. Energy sources Greenhouse effect Pollution Ozone problem Food additives

Why Study Chemistry? Think about current issues in the news. Energy sources Greenhouse effect Pollution Ozone problem Food additives Drugs

INTRODUCTION CHEMISTRY: A science that deals with the composition, structure, and properties of substances and of the changes they undergo. There are six major subdivisions of Chemistry:

Organic chemistry: Covers the compounds of carbon and hydrogen (hydrocarbons). All compounds derived from hydrocarbons.

Organic chemistry: Covers the compounds of carbon and hydrogen (hydrocarbons). All compounds derived from hydrocarbons. Inorganic chemistry: Covers all the elements, and all compounds, except the hydrocarbons and their derivatives.

Organic chemistry: Covers the compounds of carbon and hydrogen (hydrocarbons). All compounds derived from hydrocarbons. Inorganic chemistry: Covers all the elements, and all compounds, except the hydrocarbons and their derivatives. 3. Physical chemistry: Measurement of physical properties. Interpretation of physical and chemical properties.

Biochemistry: Study of pure substances and chemical reactions in living systems.

Biochemistry: Study of pure substances and chemical reactions in living systems. Analytical chemistry: Measurement of the amounts of substances. Measurement of chemical composition of materials. Separation of the components of mixtures.

Biochemistry: Study of pure substances and chemical reactions in living systems. Analytical chemistry: Measurement of the amounts of substances. Measurement of chemical composition of materials. Separation of the components of mixtures. 6. Theoretical chemistry: Mathematical description of chemical structures and of chemical changes.

Scientific Method

Scientific Method A series of steps used to solve scientific problems.

Scientific Method A series of steps used to solve scientific problems. Objective: Some problem to be solved, e.g. how oxygen gas binds to the hemoglobin molecule in our blood.

Collection of data: Once the goal is defined, the next step involves making careful observations and collecting bits of information about the system. The bits of information are called data. The word system here means that part of the universe that is under investigation.

The information obtained may be both qualitative or quantitative.

The information obtained may be both qualitative or quantitative The information obtained may be both qualitative or quantitative. Qualitative: general and non-mathematical. E.g. the object has a blue color.

The information obtained may be both qualitative or quantitative The information obtained may be both qualitative or quantitative. Qualitative: general and non-mathematical. E.g. the object has a blue color. Quantitative : numerical – related to measurements. E.g. the density is 2.1 g/ml.

Law: After a large amount of data has been collected, it is often desirable to summarize the information in a concise way. This summarizing statement is called a law.

Law: After a large amount of data has been collected, it is often desirable to summarize the information in a concise way. This summarizing statement is called a law. A law is a concise verbal or mathematical statement of a relation between phenomena that is always the same under the same conditions.

Hypothesis: Once enough information has been gathered, a tentative explanation for the observations can be formulated – this is the hypothesis.

Hypothesis: Once enough information has been gathered, a tentative explanation for the observations can be formulated – this is the hypothesis. Further experiments are devised to test the validity of the hypothesis in as many ways as possible.

The hypothesis provides tentative explanations that must be tested by many experiments. If the hypothesis survives such tests, the hypothesis develops into a theory.

The hypothesis provides tentative explanations that must be tested by many experiments. If the hypothesis survives such tests, the hypothesis develops into a theory. Theory: A theory is a unifying principle that explains a body of facts and those laws that are based on them. Theories are constantly being tested. If a theory is proved incorrect by experiment, then it must be discarded or modified, so that it becomes consistent with experimental observations.

Scientific progress is made by modifying old laws and theories or replacing them with new ones.

Summary – the sequence

Summary – the sequence 1. Objective

Summary – the sequence 1. Objective Data collection

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law 4. Hypothesis (tentative explanation)

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law 4. Hypothesis (tentative explanation) Test hypothesis

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law 4. Hypothesis (tentative explanation) Test hypothesis Formulate theory

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law 4. Hypothesis (tentative explanation) Test hypothesis Formulate theory 7. Further testing

Summary – the sequence 1. Objective Data collection Summarize data, generalization, formulation of law 4. Hypothesis (tentative explanation) Test hypothesis Formulate theory 7. Further testing 8. Rejection or modification of theory as required to account for new observations.

Some basic definitions Matter: Anything that occupies space and possesses mass is called matter.

Some basic definitions Matter: Anything that occupies space and possesses mass is called matter. Mass: The mass of a body is a measure of the quantity of matter contained in that body.

Some basic definitions Matter: Anything that occupies space and possesses mass is called matter. Mass: The mass of a body is a measure of the quantity of matter contained in that body. Weight: Refers to the force which gravity exerts upon an object. Unfortunately, chemists very frequently use the word “weight” when they mean mass.

Substance: A substance is a form of matter that has a definite composition and distinct properties. Examples: gold, water, oxygen.

Substance: A substance is a form of matter that has a definite composition and distinct properties. Examples: gold, water, oxygen. Mixture: A combination of two or more substances in which the substances retain their identities. Examples: air, a solution of table sugar (sucrose) in water.

Substance: A substance is a form of matter that has a definite composition and distinct properties. Examples: gold, water, oxygen. Mixture: A combination of two or more substances in which the substances retain their identities. Examples: air, a solution of table sugar (sucrose) in water. Note: Mixtures do not have constant composition; samples of air collected in Los Angles will have different composition from samples collected in Eau Claire.

There are two types of mixtures: homogeneous and heterogeneous.

There are two types of mixtures: homogeneous and heterogeneous There are two types of mixtures: homogeneous and heterogeneous. Homogeneous mixture: The composition is the same throughout. Example: a small amount of sugar completely dissolved in water.

There are two types of mixtures: homogeneous and heterogeneous There are two types of mixtures: homogeneous and heterogeneous. Homogeneous mixture: The composition is the same throughout. Example: a small amount of sugar completely dissolved in water. Heterogeneous mixture: A mixture in which the individual components remain physically separate and can be seen as separate components. Example: a mixture of sugar and sand.

Any mixture, be it homogeneous or heterogeneous, can be put together and then separated into pure components without any change in the identity of the components, by physical means.

For example: sugar can be removed from a homogeneous sugar solution by evaporating off the solvent water.

For example: sugar can be removed from a homogeneous sugar solution by evaporating off the solvent water. A sugar/sand mixture could be separated by dissolving the sugar in water, drying the sand, and reclaiming the sugar by evaporation of the solution.

For example: sugar can be removed from a homogeneous sugar solution by evaporating off the solvent water. A sugar/sand mixture could be separated by dissolving the sugar in water, drying the sand, and reclaiming the sugar by evaporation of the solution. In the physical separation process, there has been no change in the composition of each substance making up the mixture.

Physical property: Any property of a substance that can be observed without permanently* changing the substance to form some other substance. Examples: color, density, melting point. * Some exceptions to this. E.g. some compounds decompose at their melting point. A physical property can be specified without reference to any other substance.

Chemical property: Any property of a substance that cannot be studied without resulting in a permanent change of the substance to form some other substance.

Chemical property: Any property of a substance that cannot be studied without resulting in a permanent change of the substance to form some other substance. Example: sodium metal is very reactive with water.

Chemical property: Any property of a substance that cannot be studied without resulting in a permanent change of the substance to form some other substance. Example: sodium metal is very reactive with water. Reactivity is a chemical property that refers to the tendency of a substance to undergo a particular chemical reaction.

Element: An element is a pure substance that cannot be separated into simpler substances by chemical means.

Element: An element is a pure substance that cannot be separated into simpler substances by chemical means. Compound: A pure substance composed of two or more elements chemically united in fixed proportions.

Element: An element is a pure substance that cannot be separated into simpler substances by chemical means. Compound: A pure substance composed of two or more elements chemically united in fixed proportions. Atom: The smallest particle of an element that retains the chemical nature of the element.

Element: An element is a pure substance that cannot be separated into simpler substances by chemical means. Compound: A pure substance composed of two or more elements chemically united in fixed proportions. Atom: The smallest particle of an element that retains the chemical nature of the element. Molecule: A structure consisting of two or more atoms that are chemically bound together and behave as an independent unit.

Energy: Is the capacity to do work or produce change.