lab practical Flashcards
watts=
amps x volts
when reading a burette…
-read at eye level with the liquid
-read at the BOTTOM of the meniscus
-should be numbers given plus 1 sig fig (so 2 decimal places)
-DO NOT FORGET UNITS
what tool would be used to measure 10.00mL of water?
a graduated cylinder would be the best option
reading a ruler
-use the given digits plus one
-ex) if the ruler reads 7 you would add another digit like 7.2 (ruler with less lines btw inches) OR if the ruler reads 7.4 you would put something like 7.45 (ruler with more lines btw inches)
-DO NOT FORGET UNITS
what types of compounds are LESS soluble in seawater than in water?
-sea water includes ions such as Na, Cl, Mg, Sulfate, Ca, and K
-so in compounds that have a common ion, it will solubilize less in sea water than it would in water
how do you find the Keq of a graph?
-it is the slope of the graph
-if it is negative, take the absolute value and make it positive
when looking at a graph of absorbance on the Y axis and Concentration on the X axis…
-Concentration=X, so if looking for absorbance plug in X to get Y (absorbance)
-Absorbance=Y, so if looking for concentration, plug in y value to get the X value (concentration)
-A v B (usually A is y and B is x)
What would impact the freezing point the most when looking at Van Hoff?
-Freezing point LOWERS with increasing van’t hoff
-so if the vant off is large, then the freezing point lowers
-reminder, van’t hoff is ideally the number of ions in a compound (more ions, less freezing point)
how to find missing concentration or volume?
M1V1=M2V2
-don’t forget units
PH=
pka + long [HA/A]
-the conjugate over the acid/base
How do you get the pka from a PH graph?
you look at the half equilivance point
PH= pka at 1/2 euililivance point
what is the equilivance point on a graph?
when the moles of HA = the moles of A
-when the line is close to vertical
typically, as the van’t hoff increases
concentration decreases
-so less concentration more van’t hoff and vie versa
