Integrated Science
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42 terms
Terms | Definitions |
|---|---|
 safety lab procedures | tie back hair & loose clothing, no eating & drinking, don't touch hot objects, waft the substance to get its odor, notify the teacher first if there's an accident |
| scientific method | an organized plan for gathering, organizing and communicating information with the goal of solving a problem or better understanding an observed event |
| scientific method steps | make observations, form hypothesis, test hypothesis, draw conclusion, develop a theory |
| scatter plots | graph of data used to determine whether a pattern or trend exists |
| independent variable | variable that is changed in an experiment |
| dependent variable | the outcome factor; the variable that may change in response to manipulations of the independent variable. |
| scientific notation | a way of expressing a value as the product of a number between 1 and 10 and a power of 10; makes very large or small numbers easier to work with |
| physical properties | any characteristic of a material that can be observed or measured without changing the composition of the sumbstances in the material |
| examples of physical properties | viscosity, conductivity, malleability, hardness, melting point, boiling point, density |
| freezing point | the temperature at which a substance changes state, either from a liquid to a solid OR another name for melting point, when substance changes from a solid to a liquid |
| boiling point | the temperature at which a substance changes from a liquid to a gas, also the temp at which a substance condenses |
| malleability | ability of a solid to be hammered without shattering |
| 100 degrees Celsius | Boiling point of water |
| density | can be used to test the purity of a substance; the ratio of mass of a substance to its volume |
| examples of physical changes | cutting a piece of paper, crumpling a piece of paper, ripping a piece of paper |
| chemical properties | any ability to produce a change in the composition of matter; in effect, producing a new substance |
| evidence of chemical changes | color change, formation of a gas, formation of a precipitate |
| pure substance | matter that always has exactly the same fixed, uniform composition ex. table salt and table sugar |
| element | a substance that cannot be broken down into simpler substances; it contains only one type of atom |
| compound | a substance that is made from two or more simpler substances and can be broken down into those simpler substances; always contains two or more elements |
| impure substances | matter made up of two or more elements or compounds ex. heterogeneous mixture or homogeneous mixture. |
| heterogeneous mixture | a mixture in which the parts are noticeably different from one another ex. sand |
| homogeneous mixture | mixture in which the parts are so evenly distributed that it is difficult to distinguish one substance from another ex. swimming pool water |
| atom | the smallest particle of an element |
| Dalton's Theory | Dalton proposed the theory that all matter is made up of individual particles called atoms, which cannot be divided |
| Thomson's Model | "Plum Pudding Model" (chocolate chip icecream) ~ Stated an atom had a neutral charge; the atom had a positively charged mass of matter with negative negative charges spread evenly throughout |
| Rutherford's Experiment | "Gold Foil" Experiment; according to Rutherford's model all of an atom's positive charge is concentrated in its nucleus; the charge of the nucleus cause those alpha particles that came close to it to "bounce" back |
| Subatomic Particles | parts contained within the atom; protons, electrons and neutrons |
| Protons | positively charged subatomic particle, found inside the nucleus (symbols for: p+, p, +) |
| Electron | negatively charged subatomic particle, found outside the nucleus on the orbitals (symbols for: e-, e, - ) |
| Neutron | neutral (no charge) subatomic particle, found inside the nucleus (symbols for: n ) |
| ground state | a state in which all the electrons in an atom have the lowest possible energies |
| excited state | a state in which an atom has a higher potential energy than it has in its ground state; an atom is less stable in an excited state |
| What happens to an atom when it moves from excited state to ground state? | (pg 118) "Eventually, the electron that was promoted to a higher energy level loses energy, and the atom returns to the ground state" that is more stable |
| How many electrons can be held in the first? second? and third energy levels? | Maximums of: 2 on the first energy level; 8 on the second energy level; 18 on the third energy level |
| Groups (on the Periodic Table) | Each column down on the Periodic Table is a Group; propoerties of elements repeat in a predictable way when atomic numbers are used to arrange elements in groups |
| Period (on the Periodic Table) | Each row (across) is a period; elements become less metallic and more non-metallic in their properties from left to right across the Periodic Table |
| Atomic Number | a unique number for each element that equals the number of protons in an atom of that element; Atomic number increases from left to right and top to bottom on the Periodic Table |
| Atomic Mass | is a value that depends on the distribution of an element's isotopes in nature and the masses of those isotopes; Atomic Mass also increases from top to bottom and left to right on the Periodic Table |
| Atomic Mass Unit (amu) | 1/12 the mass of a carbon-12 atom |
| How are elements classified? | as metals, non-metals and metalloids |
| Valence electrons | electrons on the outermost energy level of an atom; elements in the same group (column) have the same number of valence electrons (except He); the number of valence electons increases from left to right across the table |
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