Chemistry Midterm Study Guide

Prefix divide by
Pico-
Nano- milli- 0.000,000,000,001
0.000,000,001
0.001 centi- 0.01 deci- 0.1 deka- 10 hecto- 100
Kilo- 1,000
Mega
1 kcal = 1000 cal
1 Cal= 1 kcal
1 cal = 4.184 1,000,000

• Neutral atoms contain the same number of electrons and protons.
• Components of a mixture can be separated (purified) by physical means.
• Physical changes alter a substance without any changes to the chemical composition.
• Chemical change involves breaking down a substance into other substances.
• Chemical bonds are broken and reformed
• Group 1 – alkali metals (light blue)
• Group 2 – alkaline earth metals (yellow)
• Group 17 – halogens (pale yellow)
• Group 18 – noble gases (green)
• Groups 1,2, 13-18 are the “Main Group” elements
• Groups 3-12 are the transition metals (purple)
• Left Side of PT table loses electrons, right side gains them.
• Covalent bonds formed between different elements are polar.
• In a molecule with covalent bonding, atoms are held together by sharing electrons.
• Electronegativity (EN) measures the tendency of an atom to attract electrons (increases as you move to the right)
• Greater than 1.8 = Ionic, Between 0 and 1.8 = Polar Covalent, ~0 = Nonpolar covalent
• Moles = Mole * (Number of electrons in element/ 1 mole)
• Atoms = Moles * 6.02*10^23, Mass number (Z) is the sum of protons plus neutrons
• Isotopes of an element have the same number of protons, but different numbers of neutrons.
• Isotopes of an element have the same number of protons, but different numbers of neutrons.
• As bond order increases, bond length decreases. As bond order increases, bond strength increases
• Allotropes: different forms of the same element
• Number of electron “pairs” determines electron pair geometry: 2 linear, 3 flat triangular (trigonal planar), 4 tetrahedral
• Methane CH4, Ethane CH3CH3, Propane, CH3CH2CH3 Butane. Pentane, Hexane, Heptane, Octane, Nonane, Decane

• Consider the reaction C7H16(l) + 11)O2(g) -> 7CO2(g) + 8H2)(l) : The reactants are C7H16 and O2
• Which is not a solution : Muddy Water
• There is more traffic between 8 and 9 in the morning because most people start work at 9. This is an example of a(n)____ hypothesis
• Select all of the examples that are compounds: Methane in fuel/ potassium chloride used as a salt substitute,
• The atomic size of atomic: Increases going down within a group
• The compound formed between Al and CL is correctly represented by: Al2CL
• The reaction of a metal with a non-metal typically produces a(n)______ compound, while the reaction between different non-metals typically produces a(n)_____ compound. Ionic, covalent
• An atom of phosphorus-32, also written as 32p, contains _____ protons, _____ electrons, and _____ neutrons. 15, 15, 17
• What is oxidized and what is reduced in the following reaction? 2Al + 3Br2  2AlBr3 Al is oxidized and Br2 is reduced
• A polar covalent bond is found in which of these compounds? H2O

Units 5-10

 The cation is named first followed by the anion name. EG: NaNO3 = Sodium Nitrate
 O is more electronegative than H and attracts electrons.
 High salt concentration in bathing solutions cause removal of water from cells (dessication)
 Saturation is when solution has reached the solubility limit.
 pH = −log10[molar concentrations)
 pH < 7 is acidic, pH > 7 is basic
 Acids produce H3O+ ions in solution, Bases produce hydroxide, OH−, ions in solution
 Acids donate a proton (H+), Bases accept a proton (H+)
 Level 1 holds 2 electrons maximum, 2 holds 8 maximum, 3 holds 18 maximum, and 4 holds 32 electrons maximum
 Long wavelength light has low energy (radiowaves) and short wavelength has high energy (gamma rays)
Acids
Nitric Acid HNO3
Sulfuric Acid H2SO4
Hydrochloric Acid HCl
Chloric Acid HClO3
Hydrobromic Acid HBr
Hydriodic Acid HI
Bases
Sodium Hydroxide NaOH
Potassium hydroxide KOH
Calcium Hydroxide Ca(OH)2
Barium Hydroxide Ba(OH)2
Lithium Hydroxide LiOH
 Unpaired electrons are known as free radicals.
 Antioxidant enzymes – large protein molecules annihilate free radicals
 Superoxide dismutase catalyzes conversion of O2− to H2O and O2
 “Phenols” contain a benzene ring with an OH group attached.
 Homolytic cleavage of a carbon-hydrogen bond results in two fragments each with one electron unpaired
 In the combustion process: C−C, C−H and O−O bonds are broken and C=O and H−O bonds are made.
 Chain continuation same side – Cis, opposite sides – Tran
 Fractional distillation – Heavier fractions at bottom, lighter on top
 Electrophile – proton that accepts electrons. Nucleophile – electron rich compound that shares or donates electrons
 Proteins - Primary structure is sequence of amino acids, Secondary consists of alpha helices, pleated sheets, and hairpin turns, and Tertiary is packing of secondary structures
 Disulfide- S-S, Hydrogen- O-N, Ionic- Opposite charges
 Racemic – 50:50 mixtures of R and S enatiomers
 ED50 – Produces therapeutic effect in 50%, low ED50 is desired. TD50 is toxic in 50%, high ED50 is desired
 Therapeutic Index – TD50/ED50
 In the presence of an oxidizing agent such as Cl2, Ca will___ one or more electrons to become like__: lose, argon
 In an electrochemical cell, the two reactants are solid zinc and Cu2+ ion. Which reaction occurs at the cathode in this system? Cu2+ + 2 electrons  Cu
 When a base ionizes in water, the number of hydrogen ions in the solution____ and the value of the pH___ decreases, increases
 Which of the electron arrangements represents an excited state of potassium? K[2,8,8,0,1]
 The chemical reason that addition polymerization occurs is: Attraction between nucleophilic portions of one molecule and an electrophilic region of another molecule.
 The condensation amino acids to form a polypeptide or protein is accompanied by the loss of____, while the additional ethylene monomers to form polyethylene is accompanied by the loss of____. Water, Nothing