Chemistry Study: 6 Major Areas of Chemistry

**[Chemistry]** is the study of the composition of "matter" -- (matter is anything with mass and occupies space), **6 Major Areas of Chemistry** **[Analytical Chemistry]**- concerned with the composition of substances. **[Inorganic Chemistry]**- primarily deals with substances without carbon...

**[Chemistry]** is the study of the composition of "matter" -- (matter is anything with mass and occupies space), **6 Major Areas of Chemistry** **[Analytical Chemistry]**- concerned with the composition of substances. **[Inorganic Chemistry]**- primarily deals with substances without carbon **[Organic Chemistry]**- essentially all substances containing carbon **[Biochemistry]**- Chemistry of living things **[Physical Chemistry]**- describes the behavior of chemicals (ex. stretching); involves lots of math! **[Nuclear Chemistry]** - dealing with radioactivity, nuclear processes and nuclear properties **[Pure chemistry]-** gathers knowledge for the sake of knowledge **[Applied Chemistry]-** is using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing leads to an application Chemists design materials to fit specific needs -- velcro (Patented in 1955) **[Medicine and Biotechnology]**- Supply materials doctors use to treat patient's vitamin C, penicillin, aspirin (C9H8O4) materials for artery transplants and hipbones **[Energy]** -- we constantly have greater Demands \*We can conserve it; use wisely \*We can try to produce more; oil from soybeans to make biodiesel **[Agriculture]** Produce the world's food supply Use chemistry for better productivity -- soil, water, weedsplant growth hormones **[The Environment]** both risks and benefits involved in discoveries\* Pollutants need to be 1) identified and 2) prevented\*carbon dioxide, ozone, global warming **[The Universe]** Need to gather data from afar, and analyze matter brought back to Earth composition of the planets The word **[chemistry]** comes from [ **alchemy**] -- practiced in China and India since 400 B.C. **Alchemy has two sides**: **[Practical:]** techniques for working with metals, **[Mystical]**: concepts like perfection -- gold was a perfect metal In the 1500s, a shift started from alchemy to science -- **King Charles II** was a supporter of the sciences "Royal Society of London for the Promotion of Natural Knowledge" Recognize problem (observation) Purpose possible solutions or explanations (hypothesize) Decide which solution is best (performing experiments) In the late 1700s, **Antoine Lavoisier** helped transform chemistry from a science of observation to the science of measurement -- still used today **[The Scientific Method]** A logical approach to solving problems or answering questions. **Steps in the Scientific Method** [**Observations (uses your senses**)] a\) quantitative involves numbers = 95oF b\) qualitative is word description = hot **[Formulating hypotheses(ideas)]** \- possible [ ] explanation for the [ ] observation, or [ ] "educated" guess **[Performing experiments (the test)]** \- gathers new information to help decide whether the hypothesis is valid We deal with variables, or factors that can change. **[Two types]**: 1\) **[Manipulated variable]** (or independent variable) is the one that we change 2\) **[Responding variable]** (or dependent variable) is the one observed or measured during the experiment **Outcomes over the long term** **[Theory (Model)]** \- A set of well-tested hypotheses that give an overall explanation of some natural [ex. Big Bang Theory ] **[Natural Law (or Scientific Law) ]** \- The same observation applies to many different systems; summarizes results [- ex. Newton's Law of Gravatation] A **[law]** summarizes what has happened. vs A **[theory]** (model) is an attempt to explain why it happened -- this changes as new information is gathered[.] **[CHAPTER II]** **[Estimation]** is using your knowledge of something similar in size or amount to determine the size of the new object. **[Precision]** is a description of how close measurements are to each other. **[Accuracy]** is comparing your measurement to the actual or accepted value. In the U.S. we use the English or Standard System, most of the rest of the world uses the Metric or SI System. **[Basic Types of Measurement]** **[Length:]** measures distance between objects is the distance between two points. **[Mass:]** measures the amount of matter in an object **[Volume:]** measures the amount of space something takes up **[Temperature]** is a measure of the kinetic energy of the atoms in an object. **[CHAPTER III]** **[matter:]** anything having mass and volume **[mass:]** the amount of matter in an object **[weight:]** the pull of gravity on an object **[volume]**: the space an object occupies **[composition]**: what the matter is made of **[properties]**: describes matter what it looks like, smells like, etc. how it behaves. **[atom]**: a basic building block of matter **[Elements:]** contain only one type of atom 1. **[monatomic elements]** consist of unbonded, "like" atoms 2. **[polyatomic elements]** consist of several "like" atoms bonded together diatomic elements: H2 O2 Br2 F2 I2 N2 Cl2 **["HOBrFINCl = Hoberfinckle"]** **[allotropes:]** different forms of the same element in the same state of matter **[Compounds]** contain two or more different types of atoms have properties that are different from those of their constituent elements **[Atoms]** can be altered only by nuclear means **[Molecules]** can be altered by Chemicals means **[Classifying Matter]** **[(Pure) Substances]** have a fixed composition have fixed properties **[Mixtures two]** or more substances mixed together, have varying composition, have varying properties **[The substances]** are NOT chemically bonded, and they retain their individual properties **[Two Types of Mixtures]** **[homogeneous:]** (or solution) particles are microscopic; sample has the same composition and properties throughout; evenly mixed **[heterogeneous:]** different composition and properties in the same sample; unevenly mixed **[Separating Mixtures]** involves physical means, or physical changes **[sorting:]** by color, shape, texture, etc. fil**[ter]**: particle size is different **[magnet]**: one substance must contain iron **[chromatography]**: some substances dissolve more easily than others **[density:]** "sink vs. float" perhaps use a centrifuge **[distillation:]** different boiling points **[No chemical]** reactions are needed to separate mixtures; substances are NOT bonded **[Properties of Matter]** **[CHEMICAL]** properties tell how a substance reacts with other substances **[PHYSICAL]** properties can be observed without chemically changing the substance **[EXTENSIVE]** properties depend on the amount of substance present **[INTENSIVE]** properties do not depend on the amount of substance **[Physical Change]** The formation of a mixture **[Chemical Change]** The formation of a compound **[Energy Changes]** endothermic change: system absorbs heat exothermic change: system releases heat **[CHAPTER IV]** The Greek **[philosopher Democritus (460 B.C. -- 370 B.C.)]** was among the first to suggest the existence of atoms (from the Greek word "atomos") He believed that atoms were indivisible and indestructible **[Dalton's Atomic Theory (experiment based!) John Dalton(1766 -- 1844)]** Atoms of different elements combine in simple whole-number ratios to form chemical compounds In chemical reactions, atoms are combined, separated, or rearranged -- but never changed into atoms of another element. All elements are composed of tiny indivisible particles called atoms Atoms of the same element are identical. Atoms of any one element are different from those of any other element. **[Discovery of the Electron]** **[In 1897, J.J. Thomson]** used a cathode ray tube to deduce the presence of a negatively charged particle: the electron **[Cathode ray tubes]** pass electricity through a gas that is contained at a very low pressure. **[1916 -- Robert Millikan]** determines the mass of the electron: 1/1840 the mass of a hydrogen atom; has one unit of negative charge **[Conclusions from the Study of the Electron:]** All elements must contain identically charged electrons. **[Atoms are neutral]**, so there must be positive particles in the atom to balance the negative charge of the electrons **[Electrons have so little mass]** that atoms must contain other particles that account for most of the mass **[Eugen Goldstein in 1886]** observed what is now called the "proton" - particles with a positive charge, and a relative mass of 1 (or 1840 times that of an electron) **[1932 -- James Chadwick]** confirmed the existence of the "neutron" -- a particle with no charge, but a mass nearly equal to a proton