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MCAT Chemistry

Subjects : mcat, science
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. The weight in grams of compound that can be substituted by 1 atom of Hydrogen. GEW = MW / # of acidic Hyrdogens






2. 1913 - Niels Bohr - said that electrons formed specific layers instead or random ones - said atoms atoms absorb and give off energy when the electrons move from one shell to another






3. The weight in grams of one mole of a given elementand is expressedin tems of grams per mole.






4. The energy required to remove an electron from a gaseous atom; generally increases in moving from left - to - right across a period and decreases in moving down a group






5. 2.18 x 10^-18 J/electron






6. Halogens; ns2np5 - - 2nd most reactive group - The Halogens; very active because of need to fill; form -1 ions; 7 electrons in valence shell; tend to form salts with elements from groups 1A and 2A






7. A reaction where a compound does Not change its molecular structure.






8. Second quantum number - designated by the letter 'l.' This 'angular momentum' refers to the subshells within each principle quantum energy level. It can take on the value of an integer in the 0 to (n -1) range. The four subshellscorresponding to l=0






9. Two or more atoms held together by covalent bonds






10. A reaction in which atoms of one element take the place of atoms of another element in a compound






11. A chemical bond in which one atom loses an electron to form a positive ion and the other atom gains to electron to form a negative ion






12. The pressure exerted by a vapor in equilibrium with its liquid or solid phase






13. Common definition of acids as proton (H+) donors and bases as proton acceptors






14. A fundamental constant - h - that relates the energy of light quanta to their frequency: h = 6.6 X 10^-34 joule


15. Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron - and all electrons in singly occupied orbitals must have the same spin


16. (chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight






17. Have the shape of a sphere - with the center of the sphere at the nucleus; completely symmetrical along all axes; 1s orbital is spherically symmetric and has no nodes; 2s orbital is also spherical but contains a node and is higher in energy






18. A pair of equal and opposite electric charges or magnetic poles separated by a small distance






19. Specifies the specific orbital in which the electron is most likely to be found. - Third quantum number - designated as ml. Describes a particular orbital within a subshell where an electron is very likely to be found. Possible values are integers in






20. An acid that will completely dissociate in aqueous solution - like HCl - HI - HClO4 HBr.






21. Spectrum of certain absorbed wavelengths of light corresponding to an atom's spectrum of emitted frequencies of light. Unique to each element. AAS can be used to indentify an element.






22. The vapor pressure of solution is the product of the mole fraction of the solvent and the vapor pressure of the pure solvent. P_a=X_aP_total


23. When polar molecules orient themselves such that the positive region of one molecule is close to the negative region of another molecule.






24. The amount of a substance that contains as many particles as there are atoms in exactly 12g of carbon -12






25. The center of the atom which contains the protons and neutrons; in cells - structure that contains the cell's genetic material (DNA) and controls the cell's activities






26. A subatomic particle that has a positive charge and that is found in the nucleus of an atom Charge of +1 and mass of 1.0073 amu






27. A concentration unit of a solution expressed as moles of solute dissolved per liter of solution






28. Expression of auto - ionization of water into H+ and OH- at a certain temperature - given by the product of the ions' molar concentrations. Denoted by Kw and equal to 10-






29. A subdivision of an energy level in an atom. They are divided into orbitals.






30. A horizontal row of elements in the periodic table






31. PH=pka+log[base/acid] Used in titration based problems that relates the pH or pOH of a solution to the pK and the ratio of the dissociated species.






32. The process by which a gas escapes from one container to another at lower pressure through a tiny hole in the container.






33. The solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid


34. Named after their cation and anion






35. In a solution - the substance that dissolves in the solvent






36. Alkali metals: highly reactive - therefore always compounds. - 1 valence electron +1 ion - Hydrogen H? - Lithium Li? - Sodium Na? - Potassium K? - Rubidium Rb? - Cesium Cs?






37. An equilibrium expression used to measure weak - acid strength - given by the ratio of the product of the products' molar concentrations to the product of the reactants' molar concentrations - with each term raised to the power of its stoichiometric






38. A reaction in which atoms of one element take the place of atoms of another element in a compound






39. Standard Temperature and Pressure. 273 Kelvin (0 Celsius) - 1 atmosphere (760 torr - 760 kPA).






40. A set of spectral lines that appear in the visible light region when a hydrogen atom undergoes a transition from energy levels n>2 to n=2.






41. Contains nonmetals that are non - reactive. Full outermost energy level except helium which has 2.






42. The ratio of the number of moles of solute dissolved in one kilogram of solvent. molality (M = moles solute/kg of solution)






43. A physical property of a solution that depends on the number - but not the identity - of the disswolved solute particles; example properties include vapor pressure lowering - boiling point elevation - osmotic pressure - and frezzing point depression






44. The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.






45. Mixture of 2 or more substances that distills at a constant temperature and with constant composition - even though seperately the components have different boiling points






46. Energy released when an atom or ion in the gaseous state gains an electron. Increases from left to right and from bottom to top on the Periodic Table.






47. Sol - a chemical process in which solvent molecules and molecules or ions of the solute combine to form a compound






48. Systematic pairing of a deprotonated species (base) with its protonated form (conjugate acid). Conjugates appear on opposite sides of a chemical equation.






49. Valence Shell Electron Pair Repulsion theory - stating that the three - dimensional molecular geometry about some central atom is determined by the elctronic repulsion between its bonding and nonbonding electron pairs.






50. (chemistry) a substance that changes color to indicate the presence of some ion or substance