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50 Cards in this Set
- Front
- Back
what is ohms law
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V=IR
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current measured in:
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amps
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resistance measured in:
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ohms
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squiggle means
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alternating
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two lines, one solid and one dotted means
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direct
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this law is basis for gas thermometer
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charles law
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charles law says this
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volume = constant x temperature
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why adding water to bulb extends the range of the thermometer
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PV=nRT, less gas in the tube means there is less change in the volume, so the height of the plug varies less, allowing it to move further
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advantages of a silicon temp sensor over a Hg in glass thermometer
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responds quickly, small and useful in power supplies, environmentally safer, large range, no harmful mercury
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alternating voltage setting
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V~, 3 4
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direct voltage
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V line dot dash, 3 4
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resistance
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horseshoe, 3 4
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alternating current
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A~, 2 4
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direct current
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A line dot dash, 2 4
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numbering of multimeter ports
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1 3
2 4 |
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calculate Rf value
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Rf=(distance moved by component)/(distance moved by mobile phase front)
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mobile phase in paper chromatography
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2:1 propanol to water
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stationary phase in paper chromatography
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piece of chromatography paper
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use "like dissolves like" principle to rationalize relative Rf values
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sample moves farther because it is the same polarity as mobile phase. something of the opposite polarity does not move very far.
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define retention volume Vr
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Vr is the volume of the mobile phase required to carry a component through the chromatographic system.
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what does a larger Vr mean about a component's ability to interact with the liquid chromatography column?
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higher Vr means solutions are less alike and the sample is harder to dissolve
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how do you get the best chromatographic seperation?
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maximize component migration differences of all components and minimize the component spreading that occurs
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stationary phase of gas chromatograph
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tide detergent
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mobile phase of gas chromatograph
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natural gas
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why do samples have different retention times?
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affinity of gas to the tide, length and tightness of column, gas flow rate
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difference between CFC and HCFC?
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CFCs have a smaller molar mass, more stable and volatile, cheaper. HCFCs are being phased out because of environmental health problems. carbon halogen bonds do not break down easily causing environmental longevity
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practical applications of GC?
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science, medicine, and industry; trace pollutants in air, trace drugs in blood, examine petroleum refinery products
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a voltaic cell is
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spontaneous
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an electrolytic cell is
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nonspontaneous, must force current through it
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in electrolytic, anode is:
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positive
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in electrolytic, cathode is:
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negative
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in voltaic, anode is
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negative
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in voltaic, cathode is
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positive
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how do you make a lead acid battery?
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fill a well with sulfuric acid, connect two pieces of lead to a meter, charge it by connecting it to a 9v battery
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what happens when a battery has run down
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Ecell at equilibrium goes to Eocell
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define chemical kinetics
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study of various factors that control the rates of reactions and the study of mechanisms by which reactants become products
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what is the rate of reaction determined by?
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temperature, concentration, diffusion rate, presence of catalyst
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what is the rate determining step
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slowest reaction step, determines the rate of the reaction
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give definition for mechanism of a reaction
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all of the actual elementary steps involving molecules that take place simultaneously or consecutively and that added together give the observed overall reaction
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define activation energy
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amount of enery required for reaciton to take place
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pink color means
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base
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purple color means
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acid
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for an indicator, where do you want the equivalence point?
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half way to equivalence point
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what effect does a dilution have on pH of a buffer
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no effect
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what effect does a dilution have on buffer capacity?
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capacity decreases
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pH = ?
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pKa at 1/2 way to equivalence point
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henderson hasselbalch
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pH=pKa + log Q
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Ka =
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10 ^ -pKa
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why are buffers biologically relevant
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buffers keep a system at homeostasis or close to it
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what is buffer capacity
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abilty to resist small changes in pH
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