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32 Cards in this Set
- Front
- Back
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matter |
anything that occupies space and has mass |
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element |
a substance that can't be broken down to there substances |
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compound |
a substance consisting of two or more different elements |
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trace elements |
elements that are essential to humans in small amounts (iodine, fluorine,iron) |
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subatomic particles |
proton-postive electron-negative neutron-neutral |
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nucleus |
protons and neutrons in the atoms central core |
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atomic number |
number of protons |
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mass number |
sum of the number of protons and neutrons |
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atomic mass |
the sum of protons and neurons (mass number too) |
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isotopes |
different number of neutrons |
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radioactive isotope |
when the nucleus decays spontaneously, giving off particles and energy *can use them as radioactive tracers to trace things in body *can be harmful to DNA |
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electron shells |
different levels at which electrons can sit |
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chemical bonds |
when atoms share donate or receive atoms to fill their outer shells |
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covalent bond |
when atoms share electrons from the outer shell- forms a molecule *double bond when share two pairs of electrons |
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electronegativity |
atoms attraction for shared electrons (more electronegative, the more it pulls on the electrons) *nonpolar covalent bonds- when the electrons are shared equally like in H2 or O2 *polar covalent bond- when the electrons are unqually shared like in H2O where O pulls much more |
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ionic bonds |
*ion-when an atom gains or loses electrons *when two ions with opposite charges attract each other *NaCl= salt=ionic compound *Na gives its last electron to Cl to form ionic bond |
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hydrogen bond and its water qualities |
*when a polar molecule has a partial positive charge on a hydrogen, allowing it to "flirt" with molecs that are more negative *make H2O cohesive *cohesion- molecules of the same kind stick together *adhesion- the clinging of one substance to another *surface tension- a measure of how hard/easy it is to break the surface of a liquid |
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chemical reactions |
breaking existing bonds and creating new ones *reactants- starting materials *products- end materials |
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hydrogen bonds and temperature |
*to raise temp of water H bonds must be broken *evaporative cooling- when a substance evaporates and the surface of the left over liquid cools down bc the molecs with the most energy leave |
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heat |
thermal energy in transfer from a warmer to a cooler body of matter |
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temperature |
measure of the intensity of heat *average speed of molecules in a body of matter |
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Ice |
*ice floats bc it is less dense than liquid water and the molecules are more spread out than in liquid *ice isolates the water below it |
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Water as a solvent |
*good solvent bc polar |
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solution |
a liquid consisting of a uniform mixture of two or more substances |
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solvent |
the dissolving agent |
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solute |
the instance that is dissolved |
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aqueous solution |
*solution in which water is the solvent *hydrogen molecules surround and separate all the ions |
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acids |
donates hydrogen ions to solutions |
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base |
reduces the hydrogen ion concentration of a solution |
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pH scale |
describes how acidic/basic something is *pH 7 is neutral *0 is most acidic, 14 most basic |
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buffers |
substances that minimizes changes in pH |
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ocean acidification |
CO2 dissolving in seawater lowers the pH of the ocean *extraterrestrial life is based on the search for water |
