Chem Lab Exam Part 1
Chemicals of Experiment 4
0.1 M KOH, AgNO3, BaCl3, NaCl, Na2SO4 0.15 M NH3 0.2 M Na2S 0.5 M H2SO4
Materials of Experiment 2
10 mL pipette large paper clips paper weighing cup methanol waste container spatula 600 mL beaker 100 mL beaker 50 mL graduated cylinder thermometer stirring rod metal cylinders
Chemicals of Experiment 5
20 g red cabbage 30 mL pH 7 buffer phenolphthalein indicator 200 mL HCl acid solution 65 mL Ca(OH)2 unknown solution molarity
Chemicals of Experiment 6
275 mL of 1 M NaOH 100 mL of 2 M NaOH 50 mL of 3 M Na OH 175 mL of 1 M HCl 50 mL of 1 M HNO3 50 mL of 2 N H2SO4 150 mL of 3 N H3PO4 50 mL of 1 M NH3
Materials of Experiment 5
50 mL burette 10 mL pipette 75mm filter paper cabbage waste container safety goggles 100 mL beaker two 250 mL beakers 600 mL beaker two 125 mL erlenmeyer flasks 250 mL erlenmeyer flask long steam funnel 10 mL graduated cylinder
Chemicals of Experiment 2
7.5 g sodium hydroxide (NaOH) 10 mL methanol (CH3OH)
Pink; Clear
Phenolphthalein in base is ____ in color; when neutralized, the solution will become ______ in color
Zinc and Copper
Since 1962, the US penny has been made of only...
97.5%; 2.5%
Since 1982 the penny has been made of ____ zinc and ____ copper
Labeled
The axises of a graph should always be appropriately.....
Logger Pro
What is the software program that we have used to make graphs?
Scale
When creating a graph, the ______ chosen should fill as mich of the available space as possible.
Don't
When drawing a line of best fit, _______ force the cureve to pass through each point
Inversely Proportional
When two variables are ___________ ____________, a plot of y verse 1/x will give a straight line.
Same
When weighing something in the lab, it is important to use the ____ balance each time to reduce the amount of error in your measurement
Never
When weighing something on a balance, ____ weigh anything directly on the balance pan; always use a weighing boat or beaker
Neutral
a pH of 7 is...
Line of Best Fit
a smooth line that is drawn on graphs that shows the general trend of the data
Precipitate
a solid that forms and settles out of a liquid mixture
Strong Acids
acids that dissociate almost completely in aqueous solutions; pH 3 or less (HCl, HNO3, H2SO4, H3PO4, HClO4)
Weak Acids
acids that do not completely dissociate in aqueous solutions; pH 3-7 (Fe(NO3)3, FeCl3, ZnSO4, Al2(SO4)3)
Brass
an alloy consisting of essentially copper and zinc in variable proportions
Caustic Soda
another name for NaOH is...
Proportionality Constant
another name for the slope of a line (m) is....
Analytical Balances
balances found near the windows in the lab that measure to 0.1mg or 0.0001g
Metler Balances
balances found on the bench tops in the lab that measure to 1mg or 0.001g
Strong Bases
bases that completely dissociate in aqueous solutions; pH 11 or higher (NH3, KOH, NaOH, Ca(OH)2
Weak Bases
bases that do not completely dissociate in aqueous solutions; pH 7-11 (Na2CO3, Na2S, Na3PO4)
Materials of Experiment 4
clean 3" test tubes
Blue
color of Cu^2+ ion in aqueous solutions
Yellow
color of Fe^2+ ion in aqueous solutions
Green
color of Ni^2+ ion in aqueous solutions
Red
color of the calorimeter used for acids
Blue
color of the calorimeter used for bases
Acids
compounds that increase the concentration of the H+ ion when they dissolve in water
Bases
compounds that increase the concentration of the OH- ion when they dissolve in water
Materials of Experiment 6
computer with LoggerPro and temperature probes 2-50 mL graduated cylinders 250 mL beaker 2 thermos
Goals of Experiment 2
develop weighin and pipetting skills demonstrate items difficult to weigh accurately perform a density calculation
Hand Drawn
for the graph in Part 4 of Experiment 1, the line of best fit was...
D = m/v
formula for calculating density
M1V1 = M2V2
formula for dilution
q = mc∆T
formula for heat
qCal = -(qHot + qCool)
formula for heat of the reaction
pH = -log H+
formula for pH
m = (y2 - y1)/(x2 - x1)
formula for slope
Ccal = qCal/∆T
formula for the calorimeter constant
xy = m
formula for two variable which are inversely proportional
Absolute Uncertainty
instrumental error; instruments and lab equipment have inherent limitations in the accuracy of their measurements
Digital Equipment
lab equipment (electronic balances) that has an absolute uncertainity in measurement of +/- 2 in the last reported decimal
Analog Equipment
lab equipment (graduated cylinders, beakers) that has an absolute uncertainty in a measurement of 1/5 of the smallest division
Calculations Performed in Experiment 6
moles of water produced in each reaction molarity of water ∆T = Tfinal - Tinitial ∆Hneutralization = -(ms∆T + Ccal∆T)
mg/L
ppm =
Goals of Experiment 5
preparation of an acid/base indicator from cabbage gaining practice in acid/base titration technique find the molarity of unknown Calcium Hydroxide solution
Preparation of Indicator from Cabbage
procedure carried out in Part 1 of Experiment 5; involved boiling cabbage, filtering out the solution, and using the solution as a pH indicator
Calibrating the Calorimeter
procedure carried out in Part 1 of Experiment 6; involved mixing hot DI water with room temperature DI water to determine the calorimeter constant
Titration with Phenolphthalein as the Indicator
procedure carried out in Part 2 of Experiment 5; involved the neutralization of Ca(OH)2 by HCl with a stock indicator, using a burette to perform three titrations
Measuring Reaction Temperatures
procedure carried out in Part 2 of Experiment 6; involved mixing various volumes and concentrations of acid and bases to measure the heat for reaction
Titration with Cabbage Indicator
procedure carried out in Part 3 of Experiment 5; involved the neutralization of Ca(OH)2 by HCl with a homemade indicator, using a burette to perform three titrations
Svante Arrhenius
scientist who proposed that certain compounds, commonly known as salts, dissolve in water by dissociating into positive and negative ions
NH3; Na2S
solutions of _____ and ______ in water have characteristic odors
H2S
solutions that contain ____ will produce gas and an odor of rotten eggs
CO3^2-; HCO3^-
solutions that contain _____ or _____ will produce carbon dioxide
Aqueous Solutions
solutions where dissociated ions are bound tightly to neighboring water molecules
Bright Green; Light Blue
the cabbage indicator in base is ________ in color; when neutralized, the solution will become ________ in color
Brown
the color of the nitrogen dioxide given off by the copper blue solution as the penny dissolved
Vertical
the dependent variable is plotted on the ________ axis
y = mx + b
the equation for a linear relationship when the dependent variable does not equal zero when the independent variable does
y = mx
the equation for the simplest form of a straight-line relationship that indicates that two variables are directly proportional
Horizontal
the independent variable is plotted on the _________ axis
Observation and Deduction
the keys to success in Experiment 4 are _____ and _____; must be able to _____ what happens when two reagents are mixed and ____ what ions might be present in the unknown sample
pH vs Volume
the one graph produced in Part 4 of Experiment 1 compared...
67%; 33%
the percent composition of brass is ___ copper and ____ zinc
Relative Uncertainty
the percentage of the absolute uncertainty compared to the measurement
Identification of Five Unknowns
the procedure carried out in Experiment 4; involved testing five compounds (strong acid, strong base, chloride salt, nitrate salt, sodium salt) by creating chemical solutions
Weighing Paper Clips
the procedure carried out in Part 1 of Experiment 2
Weighing high vapor pressure liquid
the procedure carried out in Part 2 of Experiment 2; involved methanol and the Matler balance
Weighing cold and hygroscopic materials
the procedure carried out in Part 3 of Experiment 2; involved NaOH and the Metler balance
Dipensing known volumes of liquid
the procedure carried out in Part 4 of Experiment 2; involved deionized water, pipette, burette, and graduated cylinder
Density determination
the procedure carried out in Part 5 of Experiment 2; involved NaOH and an unknown metal cylinder
Dissolving Pennies to Find PPM Copper
the procedure followed for Part 1 of Experiment 3; involved weighing a penny, dissolving it in Nitric Acid, diluting it in DI water, and using the atomic absorption spectrophotometer
Making Brass Pennies
the procedure followed in Part 2 of Experiment 3; involved weighing two pennies, immersing the pennies in hot 6M NaOH, and then using a bunsen burner
P vs V P vs 1/V V vs 1/P
the three graphs produced in Part 1 of Experiment 1 compared...
Io/I vs concentration log (Io/I) vs concentration
the two graphs produced in Part 2 of Experiment 1 compared...
V vs T 1/V vs T
the two graphs produced in Part 3 of Experiment 1 compared...
Goal of Experiment 6
to see that the amount of heat produced by a reaction depends upon the number of molecules involved
Goals of Experiment 4
use simple observations about the behavior of acids, bases and salts to identify the contents of an unknown solution
95%; 5%
From 1962 until 1982, a penny was ____ copper and ____ zinc
Origin
If the value of the dependent variable is zero when the value of the independent variable is also zero, the graph must pass through the...
Goal of Experiment 3
Measuring composition of alloys
262 mg/m^3
Methanol TLV =
2 mg/m^3
NaOH TLV =
