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56 Cards in this Set
- Front
- Back
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Do Alkanes readily participate in substitution reactions?
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No, they are relatively unreactive. They burn in air when ignited, and require vigorous conditions to undergo a substitution reaction.
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What is an addition reaction, and how readily does it occur?
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When a reagent adds to a double or triple bond, these occur readily
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Which would have a higher boiling point: a cis or trans isomer?
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A cis isomer, because it will be more polar, and therefore have intramolecular forces which must be broken in order to boil.
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Why are aromatic compounds stable?
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Due to the sp2 hybridization of each C bond and the delocalised pi bonding.
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What reactions will benzene participate in?
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Substitutions - via catalysis, but not addition because there are no double bonds.
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What is the structure of an amino acid?
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C single bonded to a carboxillic acid, and amine, and R group and an H.
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How do you oxidize a primary alcohol into a Carboxylic acid?
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Primary alcohols first oxidize into Aldehydes (KMnO4). All Aldehydes then oxidize into Carboxyllic Acid
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What do secondary alcohols oxidize to?
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Ketones
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What is ester linkage?
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O=C-O-C linkage, due to a condensation reaction between a carboxyllic acid and an alcohol group.
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How do aminos react?
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They form peptide bonds (C-N) from condensation reactions.
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How do temperature, catalysis, and chemical bonding affect nuclear reactions?
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They do not, those affect normal chemical reactions because of the interaction of electrons. Nuclear chemistry is about the nucleus.
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What happens to a proton in the nucleus during electron capture?
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It is converted into a neutron and an X-Ray is released. This may occur when the n/Z ratio is too low.
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What is the order of penetrating ability for radioactive emissions?
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Gamma rays penetrate the best, they require a thick block of lead to stop. Beta emissions can be stopped by metal or thick clothing. Alpha emissions can be stopped by skin or paper. The concept is that the smallest emissions can penetrate best, the biggest cannot.
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Why is the RBE higher for alpha particals than for Beta or Gamma particles?
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Because it is a bigger particle and gets stuck in the body, rather than passing through.
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What is the formula for REMs? (Roentgen Equivalent for Man)
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#REMs = #RADS * RBE
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Describe the stability band for the n/Z ratio
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Z up to 20, n/Z = 1
Z from 20 - 26, n/Z = 1.15 Z from 27 - 47, n/Z = 1.28 Z from 48 - 74, n/Z = 1.49 Z from 75 - 83, n/Z = 1.52 Z above 83, are radioactive and usually alpha emitters |
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What are some exceptions to the n/Z ratio?
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1/1H and 3/2He are both stable nuclei with n/Z less than 1.
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How can you tell stability from the number of protons and neutrons?
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If #n and #p are both odd, then the atom is unstable, if even it is likely unstable. Odd/Even, Even/Odd are relatively stable.
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What are isotopes that are stable but have an odd number of protons and an even number of neutrons?
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2/1H, 6/3Li, 10/5B, 14/7N
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What are the magic numbers for protons OR neutrons? (You may not add)
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2, 8, 20, 50, 82, 126
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How do you predict the type of radioactive decay?
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Look at the n/Z ratio. If there are too many protons then there will be positron emission or electron capture. If there are too many neutrons then there will be beta decay. Anything over 83 is mostly likely alpha emission.
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All nuclear ractions follow which order of kinetics?
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First order - remember that A0 and A can be anything (pressures, masses, rates), as long as they are the same.
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How do you find mass deficit and convert it to energy of a nuclear reaction?
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Mass defect is the difference between the nucleons - the atomic mass of the binded atom. It is converted to the energy of the reaction by converting the mass in g/mol to kg/mol, multiplying by C squared, and then converting from J/mol to kJ/mol.
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Which element has the highest binding energy per nucleon? Why is this important?
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Iron (mass=65) has the highest, so atoms smaller (mass) than iron undergo fusion, and atoms larger than iron undergo fission.
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What are the four regions of the atmosphere?
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Troposphere (0-10km)
Stratosphere (10-50km) Mesosphere (50-80km) Thermosphere (80-500km) |
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What are the chemical components of the stratosphere?
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N2 (78%)
O2 (21%) Ar (1%) CO2 (0.033%) and rising |
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What is photoionization and where does it occur?
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Protons/electrons from the sun strike molecules and atoms, causing molecules or atoms in the Thermosphere to lose an electron (ionize) and release a large amount of heat.
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What is photodissociation?
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Solar protons & electrons strike molecules in thethermosphere and break the bonds, releasing less heat than photoionization.
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How is the thermosphere heated?
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The reverse of the photodissociation and ionization reactions occur in the meso and thermosphere.
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How do you find out the wavelength required to break a Cl2, O2, or O3 bond?
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E = (hc)/lambda, where E = the bond energy for a single the bond
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How does Cl destroy Ozone in the stratosphere?
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UV rays break a Cl bond in CFCl3 through photodissociation. The Cl then catalyses the destruction of Ozone as follows:
Cl + O3 -> ClO + O2 ClO + O -> Cl + O2 Overall: O3 + O -> 2O2 |
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A single Cl atom can catalyze the destruction of how many O3 moleulces?
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Around 100,000
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What is the problem with CFCs?
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Chlorine is chemically inert (which solved other problems), but can catalyze the destruction of ozone.
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Why is O3 important?
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O2 absorbs higher energy UV radiation, O3 captures lower energy UV.
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How did the Ozone hole form?
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ClO from Ozone depletion reacts with NO2 at the poles, forming a dangerous compound that reacts with HCl (catalyzed by ice), which in turn causes Cl2 production. When spring comes and the area warms, Cl2 undergoes photoionization and forms 2 Cl molecules.
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What is a pollutant?
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Anything, natural or otherwise that is in the wrong place or in too much abundance. O3 in the troposphere (naturally in stratosphere) or CCl3F in the Stratosphere are pollutants.
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What is good about Freons?
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They replaced NH3 and SO2 where were toxid. They are non toxic, non flammable and chemically inert (although they dissociate with UV and catalyze O3 destruction)
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Why are freon substitutes better than freons?
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They lack C to Cl bonds which were too weak to withstand UV
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How does the Greenhouse Effect work?
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Solar radiation hits the Earth, which emits infrared radiation back into the atmosphere. Molecules in the atmosphere absorb the infrared radiation through molecular collisions, releasing energy as heat. These green house gas molecules must be polar or have the ability to be polar (so no diatomic gases). The net effect is a wamer earth.
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What are examples of greenhouse gases?
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Any molecule with a dipole moment (CO2, CH4, NO2, FREONS). H2O is dangerous because the more it heats the earth, the more H2O gets into the atmosphere causing more warmth.
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Is normal rain pH neutral?
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No, it is slightly acidic?
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What is acid rain?
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pH lower than 5.5 (4.3 in WPA), this is caused by the presence of covalent oxides (acid anhydrides) that form acids in water. E.g. SO2, SO3, CO2, and SNO2
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What are the components of photochemical smog?
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NO, NO2, O3, Hydrocarbons, Sunlight
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What is the process for the formation of photochemical smog?
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N2 + O2 -> 2NO (autoengines)
2NO + O2 -> 2NO2 NO2 + hv ->NO + O O + O2 -> O3 |
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What are the Units for Rate Law?
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0 Order = ms-1
1 Order = s-1 2 Order = m-1, s-1 3 Order = m-2, s-1 |
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Define a Catalyst and an Intermediate
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A catalyst is a reactant in an elementary step and is a product in a later step. An intermediate forms in an elementary step and is a reactant in a later step.
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What would constitute a "stress" on a system at equilibrium?
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A change in volume (favors side with more moles of gas), or temperature
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How is Kc effected by temperature?
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Higher T increases K for an endothermic reaction and decreases K for an exothermic reaction (and vise versa)
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When will Kc= Kp?
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When the number of gas moles is the same on both sides.
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Which aqueous salt ions are acidic in water?
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NH4+, Al3+, Mg2+ and other small, highly charged cations
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Which aqueous salt ions are basic in water?
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F-, CN- CO32- PO43-
CH3COO- and other organics |
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Are group IA metallic ions acidic in water?
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No, they are all spectator ions and do not participate in equilibrium.
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Are Cl- Br- I-
NO3- ClO4- SO42- basic in water? |
No, they are all spectator ions and do not participate in equilibrium.
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What is the formula for an acidic and basic salt ion in water?
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Basic: F- + H2O <> HF +OH-
Acidic: Al3+ H2O <> Al2+ + H3O+ |
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In the equation Ka*Kb=Kw, what is the value for Kw? Additionally, what is a quick way to convert from OH concentration to pH?
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10E-14. You can convert from OH concentration by taking the log of OH (not the negative log) and adding 14.
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Using the formula ΔG = ΔH - TΔS; explain which values for T, ΔS, and ΔH will result in spontaneous or nonspontaneous reactions.
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Negative ΔH and positive ΔS will be spontaneous. Positive ΔH and positive ΔS may be spontaneous.
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