1Enthalpy (delta h) is positive when the reaction is _______ (endothermic/exothermic).
endothermic
2Enthalpy (delta h) is negative when the reaction is _______ (endothermic/exothermic).
exothermic
3What is the sigfig rule for addition/subtraction?
use the number with the fewest decimal places
4What is the sigfig rule for multiplication/division?
use the number with the fewest sig figs
5All _____ digits are significant.
nonzero
6Zeroes between nonzero digits are _____.
significant
7Zeroes to the _____ of the first nonzero digits are not significant
left
8Zeroes to the _____ of a decimal point in a number are significant
right
9What is the rule for finding Z for ions?
absolute value of ion charge
10What is the rule for finding Z for acidsases?
number of H+ or OH- ions a species can react with or yield/produce
11What is the rule for finding Z for redox rxn?
number of e- exchanged
12If delta G < 0 or Q/K < 1 the reaction is _____.
favorable/spontaneous
13If delta G > 0 or Q/K > 1 the reaction is _____.
not favorable/not spontaneous
14If delta G = 0 or Q/K = 1 the reaction is _____.
at equilibrium
15What is alkalinity?
the capacity of water to neutralize acids
16The primary form of alkalinity around neutral pH is _____.
HCO3^- (bicarbonate)
17What is NOM?
natural organic matter is a complex mixture of organic substances which contain 2 key features - aromatic rings and unsaturated carbon bonds - both of which absorb UV light at 254 nm
18How is NOM measured?
using a spectrophotometer to measure absorbance at 254nm which is used to approximate concentration of NOM
19What is turbidity?
the cloudiness of water caused by suspended materials that range in size
20What are causes of turbidity?
inorganic materials (sediment, clay) and/or organic (bacteria)
21What are problems associated with high turbidity?
aesthetics, filterability (not as easily filtered), and disinfection (harder to disinfect - particles act as protectant for pathogens)
22How is turbidity measured?
using a turbidimeter, measured in NTUs
23What is pH?
the intensity of the acid or alkaline condition of a solution
24What is the importance of pH in water treatment and distribution?
coagulation, disinfection, and corrosion (low pH can cause corrosion)
25What are the 5 steps in drinking water treatment to separate dissolved and suspended particles?
rapid mixing/coagulation, slow mixing/flocculation, sedimentation, filtration, disinfection
26What steps in the drinking water treatment process do jar testers mimic?
coagulation, flocculation, sedimentation
27What are the goals of a jar tester?
destabilize a stable suspension of particles and remove NOM which is important to manage disinfectant byproducts
28Why don't all particles settle out in the process of drinking water treatment?
electrostatic stabilization (mutual repulsion of like charges) and steric stabilization (hydrophilic portion of NOM stay in the water and hydrophobic portions stick to the particle making it hard to push particles together)
29What are the two mechanisms of particle de-stabilization?
charge neutralization and entrapment in a precipitate (sweep floc)
30Exothermic reactions favor solid state at higher temperatures, _____ solubility.
reducing
31what is used to to determine how accurate a data set is?
percent error
32what is used to determine how precise a data set is?
coefficient of variation
33if the first non-significant digit > 5, the least significant digit is _________
incremented by 1
34if the first non-significant digit < 5, the least significant digit is _________
unchanged
35if the first non-significant digit = 5, raise ___ numbers to the next number but leave ___ digits unchanged
odd, even
36what is DF when comparing two data sets?
n1+n2-2
37how are Z and N related?
Z*M=N
38what is the equation for EW?
MW/Z