Introduction to Chemistry

Introduction to Chemistry Introduction American Chemical Society ACS. A large and influential professional society for professionals and students in chemistry and related fields. Biochemistry. The chemistry of living things, including the structure and function of biological molecules and the mechanism and products of their reactions. Chemistry. The study of matter and its transformations. See What is chemistry? for other definitions. Computer-Assisted Drug Design. Using computational chemistry to discover, enhance, or study drugs and related biologically active molecules. Computational Chemistry. A branch of chemistry concerned with the prediction or simulation of chemical properties, structures, or processes using numerical techniques. Dependent Variable. Compare With Independent Variable. A dependent variable changes in response to changes in independent variables. For example, in an experiment where the vapor pressure of a liquid is measured at several different temperatures, temperature is the independent variable and vapor pressure is the dependent variable. Environmental Chemistry. Chemical Ecology. The study of natural and man-made substances in the environment, including the detection, monitoring, transport, and chemical transformation of chemical substances in air, water, and soil. Experiment. An experiment is direct observation under controlled conditions. Most experiments involve carefully changing one variable and observing the effect on another variable (for example, changing temperature of a water sample and recording the change volume that results). Geochemistry. Geological Chemistry. The study of materials and chemical reactions in rocks, minerals, magma, seawater, and soil. Hypothesis. Hypotheses. Compare With Theory. A hypothesis is a conjecture designed to guide experimentation. Hypotheses are extremely useful in problem solving, and are essential in developing new theories. Independent Variable. Compare With Dependent Variable. An independent variable that can be set to a known value in an experiment. Several independent variables may be controlled in an experiment. For example, in an experiment where the vapor pressure of a liquid is measured at several different temperatures, temperature is the independent variable and vapor pressure is the dependent variable. Inorganic Chemistry. The study of inorganic compounds, specifically their structure, reactions, catalysis, and mechanism of action. Law. Natural Law; Scientific Law. Natural laws summarize patterns that recur in a large amount of data. Unlike human laws, natural laws don't forbid or permit; they describe. Matter. Matter is anything that has mass. Air, water, coffee, fire, human beings, and stars are matter. Light, X-rays, photons, gravitons, information, and love aren't matter. Medicinal Chemistry. A branch of chemistry concerned with the discovery, design, synthesis, and investigation of biologically active compounds and reactions that these compounds undergo in living things. Organic Chemistry. The study of compounds that contain carbon chemically bound to hydrogen, including synthesis, identification, modelling, and reactions of those compounds. Pharmacology. The study of drugs, which includes determination of biological activity, biological effects, breakdown and synthesis, and delivery. Pharmacognosy. Identification, isolation, and characterization of biologically active substances in living things. Physical Chemistry. Chemical Physics. A branch of chemistry that studies chemical phenomena from a physical and mathematical perspective. Physical chemistry includes chemical thermodynamics, kinetics, spectroscopy, quantum chemistry, and statistical mechanics. Scientific Notation. Exponential Notation. A system for reporting very small or very large numbers by writing the number as a decimal number between 1 and 10, multiplied by a power of 10. For example, 602000000000000000000000 is written in scientific notation as 6.02 x 1023. 0.000323 is written in scientific notation as 3.23 x 10-4. Theory. Theories. Compare With Hypothesis. Theories are well-established explanations for experimental data. To become established, the theory must experimentally tested by many different investigators. Theories usually can not be proven; a single contrary experiment can disprove a theory. Toxicology. The study of poisons, including identification, isolation, biological effects, mechanism of action, and development of antidotes. Variable. Compare With Independent Variable And Dependent Variable. A quantity that can have many possible values. In designing experiments, variables that affect measurements must be identified and controlled. For example, an experiment that measures reaction rates must control temperature, because temperature is a variable that can change the rate of reaction.