chem quatey

Compounds can be seperated into elements by

Chemical changes and mixtures can be separated by phyisical changes

2. Filtering separates mixtures based off of

differences in particle size, the larges particles are trapped on the filter paper while the soluble component goes through the filter paper and stays in the filtrate

3. Distilation seoerates mixtures based off of

differences in boiling point

4. Mass is conserved

during chemical and physical changes

5. When reading a volume of a liquid in a container

you MUST estimate by reading in between the graduated markings. [example graduated cylinder with marks at 0.1 mL you would estimate two places after decimal]

6. Ranking measuring devices from least precise to most precise

beaker, graduated cylinder, volumetric flasks, burette (The volumetric flask only has ONE line on it to measure one specific volume.)

7. the diatomic elements

H2 O2 N2 Cl2 Br2 I2 F2, When they are in a compound, their # of atoms can vary.

8. Metric equivalents

1 base = 1000 mili, 1 kilo = 1000 base

9. Density

mass/volume

10. The % composition by mass for a pure compound

does not change

11. Empirical formula rhyme

% to mass, mass to mole, divide by small, times until whole… Get the simplest whole # ratio of the moles (or atoms) in the compound.

12. The molecular formula for a compound is

a whole # multiple of the empirical formula ratio

13. % yield

(experimental/theoretical) x 100

14. % error

(experimental - theoretical)/theoretical x 100

15. The amount of product for a reaction

is determined by the limiting reactant

16. Combustion reactions make

CO2 and H2O

17. Solutions formulas

moles = (molarity)(Liters) and Liters = mole/molarity

18. M1V1 = M2V2

extremely useful for dilution calculations.

19. Oxidation #'s

H = +1 (except in a hydride when it is -1) O = −2 (except in a peroxide when it is -1).

20. Metric equivalent

10^9 nanometers = 1 meter

21. KNOW that d sub level is one energy level less than the period.

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6

22. Moving across a row on the periodic table

the Zeff increases, therefore the valence electrons are more attracted to the nucleus, therefore the atomic radius decreases and the ionization energy increases.

23. When reading a PES graph

the higher the peak, the more electrons there are in that sublevel, and a larger binding energy means that the electrons are closer to the nucleus.

24. When writing the electron configuration for a cation

remove the valence electrons first… the ones in the p-orbital and s-orbital… then you can remove d-orbital electrons if necessary

25. Isotopes of an element have

the same number of protons, but different numbers of neutrons.

26. Mass spec graphs measure

atomic masses of isotopes.

27. Elements in the same group (vertical columns) have similar

chemical and physical properties.

28. _______ are on the left side of the zig-zag line and ___________ are on the right side of this line on the periodic table.

Metals, Nonmetals

29. __________ are smaller than their atoms since you are removing valence electrons that are farther from the nucleus and _______ are larger than their atoms since adding extra electrons increases electron-electron repulsions.

Cations (+), Anions (-)

30. Lattice energy is

the energy to break an ionic bond in a compound. Lattice energy increases as the ion's charge increases. Lattice energy decreases as the radii of the ions increase. (This can be deduced from Coulomb's Law.)

31. ΔHrxn =

Bonds broken − Bonds formed (reactant bonds are broken product bonds are formed)

32. Breaking bonds is….

endothermic (BARF)

Forman bonds is…..

exothermic (BARF)

33. Exothermic reactions

(−) ΔH, feels hot, heat is a product, temperature goes up (endothermic is the opposite.)

34. Covalent bonds are formed between….

two nonmetals sharing electrons.

35. Ionic bonds are formed when

a metal transfers electrons to a nonmetal and the opposite charges attract.

36. The greater the electronegativity difference between 2 atoms

the more polar the bond becomes.

37. Carbon makes a total of…

4 bonds in a compound

38. Bond angles

4 domains = 109.5°, 3 domains = 120°, 2 domains = 180°

39. Hybrid orbitals

4 domains = sp3, 3 domains = sp2, 2 domains = sp

40. Asymmetrical molecules

dipoles DO NOT cancel

41. Symmetrical polar molecules

dipoles cancel = nonpolar molecule

42. Single bond =

sigma

43. Double bond =

= sigma + pi bond

44. Triple bond =

= sigma + 2 pi bonds

45. Formal charge involves

comparing the # of valence electrons an atom has to the # of electrons around it in the bonded Lewis structure (remember to split the bonded electrons evenly between the atoms.)

46. Obey the…

octet rule first when drawing the Lewis Dot Structure then use formal charge if necessary. Extra electrons can go on the larger central atom, and if you have too few electrons, start making some double or triple bonds.

47. IMF's from weakest to strongest

London Dispersion, dipole-dipole, hydrogen bonding, ion-dipole.

48. All molecules contain….

LDF forces, and this force gets stronger as the molecule is larger .Larger electron cloud = more LD = more polarizable.

49. All polar molecules contain….

dipole-dipole forces, and this force gets stronger as the molecule is more polar.

50. H-bonds are between a….

NOF in one compound and a hydrogen already bonded to a NOF in another compound.

51. Boiling point and melting point

increase as IMF's increase.

52. Vapor pressure and volatility

decrease as IMF's increase.

53. Molecular solids have a….

low melting and boiling points and do not conduct electricity.

54. Ionic solids have a…

high melting and boiling points and do not conduct electricity as a solid but do conduct as a liquid or aqueous.

55. SiO2 (quartz) and diamonds are

high melting and boiling points and do not conduct electricity as a solid but do conduct as a liquid or aqueous.

56. Metallic bonds are between

metals and they always conduct electricity.

57. When a molecular solid melts or boils it is the

IMF's between molecules that break, not covalent bonds.

58. Interstitial alloys form when

smaller atoms fit into gaps in a metallic crystal, substitutional alloys form when atoms of similar size replace each other in the lattice.

59. Chromatography separates

mixtures based on differences in polarity.

60. In paper chromatography the component

most similar in polarity to the mobile phase moves the farthest.

61. Gas mixtures are

homogeneous due to constant random motion.

62. Gases are

compressible because of large spaces between particles.

63. Gas pressure is caused by

collisions with container walls.

64. Pressure and volume are.

inversely related

65. Temperature and volume are

directly related

temperature and pressure are

directly related

67. PV = ____ with R = ______

nRT

0.08206

68. One mole of an ideal gas occupies

22.4 L at STP.

69. Gas pressure and moles are

directly related.

70. Molar mass

= dRT/P

71. Higher molar mass gases move

slower.

72. Temperature equals

average kinetic energy.

73. Ptotal =

Pdry gas + Pwater vapor

74. Real gases behave most ideally at

high temperature and low pressure.

75. Reactions require

correct orientation and sufficient activation energy.

76. Rate law for an elementary step depends on

coefficients.

77. Rate constant units depend on

reaction order.

78. First and second order graphs identify

k

79. Reactions speed up

with catalysts, higher concentration, surface area, pressure, and temperature.

80. Half-life for first order reactions equals

0.693/k

81. First order reactions have

constant half-life

82. Higher activation energy means

slower reaction.

83. Rate-determining step controls

rate law

84. Intermediates are produced ad a reactant then

consumed as a product

85. Catalysts are consumed as a product then

regenerated as a reactant

K_eq =

(products)x/(reactants)^y

X and the y represent the coefficients in the balenced chemical equation

What are the ony 2 phases that appear as equalilbrium expressions?

(g) gas

(aq) aqueous

What do you use for molatiry when solving equilibrium expressions?

brackets

[ ]

What do you use for Atm (pressure) when solving for equilibrium expressions?

(P_gas)

What does a large K_eq mean?

there is more products at equilibrium

What does a small K_eq mean?

There is more reactants at equilibrium

What do you do when reversuing a equilibrium reaction

1/ K_eq

What do you do when doubling a equilibrium reaction

( K_eq )²

What do you do when adding equilibrium reactions

Multiply the K’s together

What is LeChatelier’s principles all about?

Its all abount determining the Q

What happens if Q>K_eq (greater)

The reaction shifts to the left

towards the reactants

What happens if Q<K_eq (less)

Reaction shifts to the right

make more products

What DO NOT shift at equilibrium?

Catalyst and inert gases

When can change in pressure (caused by changing the volume of a container) only shift equilibrium?

If the number of gas particles is different on each side

increase in pressure favor a shift in equilibrium towards the side with LESSS moles of gas