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| What is Chemistry? | | Science | | 5 Branches | | Key Concepts |
Created By: Mrs. D. M. Spering
Created: April 2006
Revised: May 2006
Abington Senior High School
Science Department
Email
Mrs. Spering
| In order to truly understand chemistry, you need to understand these important concepts. | ||
| Anion - an atom or group of atoms with a negative charge - see also ion | Back to Top | |
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| Atom - the smallest particle of an element that retains the physical and chemical properties of that element. Atoms are made of protons, electrons and neutrons. | ||
| Cation - (cat - ion) an atom or group of atoms with a positive charge - see also ion | ||
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| Chemical Equation - expression representing a chemical reaction |
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| Chemical Formula - shows the number and types of atoms in a compound | ||
| Chemical Property - the ability of a substance to undergo a chemical reaction and to form new substances | ||
| Compound - a substance that can be separated into simpler substances only by chemical reactions | ||
| Density - ratio of the mass of an object to its volume. | Back to Top | |
| Electron - the smallest subatomic particle, orbits the nucleus of an atom. Electrons are negatively charged and actually determine the properties of atoms and elements. | ||
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| Element - a substance that cannot be changed into simpler substances under normal laboratory conditions. Hydrogen, oxygen and iron are examples of elements. | ||
| Formula Unit - lowest whole number ratio of ions in an ionic compound | ||
| Gas - least dense phase of matter. has no definite shape or volume. Carbon dioxide and air are gases. | Back to Top | |
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| Gram - common unit of mass used in chemistry (g) | ||
| Heterogeneous Mixture - a mixture that is not uniform in composition - dinner salad | ||
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| Homogeneous Mixture - also known as a solution, has a uniform composition - salt water | ||
| Hypothesis - a proposed explanation for observations, part of the scientific method | ||
| Ion- an atom or group of atoms that have a charge, with more or less electrons than protons | ||
| Isotopes - atoms of the same element hat have the same atomic number but different atomic masses due to a different number of neutrons | ||
| Liquid - intermediate state of matter, takes shape but not volume of its container. Liquids can flow. | Back to Top | |
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| Liter - common unit of volume in chemistry (L) | ||
| Mass - is the amount of matter in an object - usually measured in grams or kilograms. Mass is NOT weight. The mass of an object does not change when on the moon, for example. The weight of an object will change. | ||
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Matter - is anything that has mass and takes up space (has volume) | |
| Metal - includes most of the known elements. Sodium, silver and lead are metals. Metals are malleable, lustrous and conduct heat and electricity. | ||
| Metalloid - also called a semi-metal, includes silicon and germanium. Have properties intermediate to metals and non-metals. |
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| Meter - common unit of length in chemistry (m) | ||
| Mixture - a physical blend of two or more substances that are not chemically combined. Salt water and a dinner salad are two examples of mixtures. | ||
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| Molar Mass - mass of one mole of a substance (g/mol) | ||
| Mole - the most important unit in Chemistry! The amount of a substance that contains Avogadro's number of units of that substance (6.02x10^23) | ||
| Molecule - neutral chemically bonded group of atoms that act as a unit - H2O (water) is a molecule | ||
| Neutron - subatomic particle with no charge, found in the nucleus with the protons | Back to Top | |
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| Non-metal - class of elements that includes oxygen, sulfur and hydrogen. Are not good conductors of electricity and heat, and are often liquids or gases. | ||
| Nucleus - massive, dense center of an atom, contains the protons and neutrons | ||
| Observation - information gathered by using the senses, first step of the scientific method | ||
| Periodic Table - an arrangement of the elements according to their chemical and physical properties | ||
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| Physical Change - an alteration of a substance that does not affect its chemical composition | ||
| Proton - positively charged subatomic particle found in the nucleus of an atom | ||
| Scientific Method - method of inquiry involving observation, hypotheses & experiments | Back to Top | |
| Solid - most dense state of matter, cannot flow, does not take shape or volume of its container |
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| Solution- homogeneous mixture, only has 1 phase (uniform composition) Salt water is an example | ||
| Substance - sample of matter having a uniform and definite composition, either an element or a compound | ||
| Theory - thoroughly tested model that explains why experiments give certain results | ||
| Vapor - substance that is usually a liquid or solid at room temperature in the gaseous state, water vapor, for example, is gaseous H2O | ||
| Volume - the space occupied by a sample of matter | ||
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| Top of Page | |
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| What is Chemistry? | | Science | | 5 Branches | | Key Concepts | |
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Created By: Mrs. D. M. Spering |
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