Environmental Chemistry Flashcard
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Unlock answers| What makes water unique/essential to life? |
solid form is less dense than the liquid form high specific heat excellent solvent high boiling and melting point |
| Why does water have such strong intermolecular forces? |
| It is highly polar and has hydrogen bonding |
| What is an intermolecular force? |
a nonbionding force the force exists between molecules they influence the physical properties of the substance |
| What is an intramolecular force? |
a bonding force these forces exist within each molecule they influence the chemical properties of a substance |
| What elements must be present for a Hydrogen bond to occur? |
| O, F, or N |
| What do H-bonds to to melting and boiling points? |
| they elevate melting and boiling points |
| Why is ice less dense than water? |
| the bent shape of water and the Hydrogen bonding arrangement make a hexagonal crystal structure when solid that is less dense than liquid |
| Why is ice important to aquatic life? |
| It insulates water beneath, allowing aquatic life to survive winters |
| Why do we flash freeze our food? |
because ice crystals will rupture tissues and the slower the freezing, the larger the crystals/tissue rupture will go flash freezing makes smaller crystals |
| Why do substances form a meniscus? |
| due to capillary action and adhesive forces, the liquid has adhesive forces and is attracted to the container |
| What kind of molecules have London (dispersion) forces as the primary intermolecular force? |
| non-polar molecules have this |
| why do London forces occur? |
| they occur because of the instantaneous dipoles created by random electron movement and are relatively weak forces with low boiling/melting points |
| can a dipole in one molecule induce a dipole in a neighboring molecule? |
| yes it can |
| What do London forces have to do with Molar mass? |
| they increase as molar mass increases, so boiling points and melting points also increase with molar mass |
| what does surface area have to do with london forces and melting and boiling points? |
| the greater the surface area, the greater the london forces and melting and boiling points |
| Rank in order of strongest to weakest the commong bonding/nonbonding forces |
Ion-dipole H bond Dipole-dipole Dipole-induced dipole ion-induced dipole dispersion |
| what molecules or ions can polar solvents dissolve? and non-polar solvents? |
polar solvents can dissolve polar molecules or ions non-polar solvents dissolve non-polar solutes |
| What is the difference between temperature and heat? |
Heat is a flow of energy due to a temperature difference Temperature is a measure of the random motions of the components of a substance |
| what is the specific heat? |
| the amount of energy required to raise the temperature of one gram of a substance by one degree celsius? |
| what is the equation to find amount of heat? |
Q=s*m*Δt where Q = amount of heat s = specific heat m - mass and Δt = change in temperature |
| what is the heat of fusion? |
the energy required to melt 1 mole of a solid
specific to the substance |
| what is the heat of vaporization? |
| the energy required to boil one mole of a liquid |
| why is the high specific heat of water important? |
| it moderates temperature fluctuations and the high heat of vaporization has strong cooling effect |
| what is hard water, what ions are involved, and why is it a problem? |
water with high amounts (>300 ppm) of Ca2+, Mg2+, and to a lesser extent Fe2+
It's a problem because it forms mineral deposits when it evaporates and it prevents proper lathering of soap and fomrs insoluble "soap scum" (spots on your dishes/dirty shower) ; it's also a problem b/c to treat it we put phosphates in detergents which, when released into the environment, can cause eutrophication in ponds/aquaecosystems |
| What steps to we take to soften water? |
we use ion exchange resins that exhange Ca2+ and Mg2+ for K+ or Na+
we also use charcoal filters (household ones use an ion exhange resin to soften water) |
| what is the structure of soap |
| it has a non-poar tail and a polar head (like a phospholipid bilayer) |
| cholera, typhoid, cryptosporidiosis and ecoli in water |
| finish this card later |
| why we use flouride |
| finish this card later |
| how to calculate ppm and ppb and what they mean |
| finish this card later |
| groudwater contamination by fertilizers, pesticides, gasoline additives, volatile organic compounts (VOCs) |
| finish later |
| steps of wastewater treatement |
| later |
| how charcoal finters/household filters work |
| later |
| bottled water vs tap water industry and expense |
| later |
| treated water, natural and municipal sources |
| later |
| bottled water, is it safer than tap? |
| generally, no |
| environmental cost of plastic used in manufacturing and transportation |
| bottled water blah later |
| Describe a saturated and an unsaturated hydrocarbon |
* saturated has every possible bond given to hydrogen *unsaturated does not have all given to hydrogen, some double/triple bonds or other elements |
| What is the difference between an aliphatic or aromatic hydrocarbon? |
both contain six membered carbon rings Aliphatic can be saturated or unsaturated saturated = alkanes, unsaturated = alkenes or alkynes and have double or triple bonds may be chains or rings (ring molecules have 2 less H than chain so the ends can join) chains may be straight or branched Aromatics contain 1 or more 6 C unsaturated rings (benzene rings) chemical reactions different than alkenes resonance hybrid all C-C bond lengths and bond angles are identical |
| how stable are hydrocarbons and how do they break down? |
| they are very stabble but burn with substantial release of heat |
| what is the general formula for an alkane |
| CnH2n+2 |
| What is the general formula for an alkene? |
| CnH2n |
| What is the general formula for a cyclohexane? |
| CnH2n (but it's in a ring) |
| what is the general formula for alkynes? |
| CnH2n-2 |
| What is an isomer? |
| a molecule with the same molecular formula but different arrangements of the atoms |
| what are the prefixes from 1-10 carbons |
| meth, eth, prop, but, pent, hex, hept, oct, non, dec |
| know how to draw alkanes, alkenes, cycloalkanes, and alkynes including numbering, suffixes, and branching |
| later |
| what kind of ring and electrons are associated with aromatics? |
| they have a 6-membered flat ring with delocalized electrons |
| what are some specific aromatics? |
| benzene, toluene, styrene, and phenol |
| what are the functional groups |
| later |
