Idea Transcript
Student Name
Marking scheme Prelab exercise Lab performance Sig figs, units Calculations Crystals
Lab Partner Demonstrator Lab Section DATA SHEET
Preparation of a Coordination Compound Step 1
Copy the balanced equation for the preparation of FeC2O4.2H2O.
Mass taken of FeSO4(NH4)2SO4.6H2O
or
mol
Mass of H2C2O4.2H2O
or
mol
Limiting reagent is Theoretical yield of FeC2O4.2H2O Step 2
mol
Copy the balanced equation for the preparation of K3Fe(C2O4)3.3H2O from FeC2O4.2H2O.
Theoretical yield of K3Fe(C2O4)3.3H2O (based on FeC2O4.2H2O as limiting reagent) and in grams Mass of watch glass and K3Fe(C2O4)3.3H2O Mass of watch glass Yield of K3Fe(C2O4)3.3H2O Percent Yield of K3Fe(C2O4)3.3H2O Description of product crystals, i.e. size, colour, shape, etc. :
mol g
WORK SHEET Keep extra digits in all calculations when possible. Keep track of the extra digits by underlining or bracketing them. Do not show calculations to find molar mass. Step 1 Calculate moles of FeSO4(NH4)2SO4.6H2O
Calculate moles of H2C2O4.2H2O
Limiting reagent - explain or show mathematically why you choose this to be the LR (Do not just give the definition of a LR)
Step 2 Calculate the theoretical yield, in grams, of K3Fe(C2O4)3.3H2O
Calculate the percent yield of K3Fe(C2O4)3.3H2O
Prelab Exercise
Name
This exercise reviews the calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. (Do not show calculations to find molar masses.) a.
If you weighed out the following quantities of each reagent, which would be the limiting reagent in Step 1, the synthesis of FeC2O4.2H2O ? Show and explain your work. Ferrous ammonium sulphate hydrate 2.45 g Oxalic acid hydrate 1.35 g
b.
Using your data from question a, calculate the theoretical yield in grams of the potassium trioxalatoferrate (III) trihydrate complex.
Student Name
Marking scheme Prelab exercise Lab performance Sig figs, units Calculations NaOH and Unkn
Demonstrator Lab Section
DATA SHEET Acid-Base Titration, a Quantitative Analysis Part 1 Standardization of NaOH solution Mass of boat and sample Mass of boat after transfer Mass of sample transferred Final burette reading Initial burette reading Volume of NaOH Calculated molarity of NaOH Lab. average molarity of NaOH (from your demonstrator) % deviation of your value from lab. average Part 2 Molar Mass of an Acid
Unknown #
ia =
Mass of boat and sample Mass of boat after transfer Mass of sample transferred Final burette reading Initial burette reading Volume of NaOH Calculated molar mass Average values for the molar mass of the acid - the averages below will be the same number but may have different SF Average molar mass of the acid
( SF method)
Average molar mass of the acid
ssd
(ssd method)
WORK SHEET Use extra digits in all calculations when possible. Part 1 Molarity of the NaOH Calculate the molarity of NaOH solution
equation (3)
Calculate the % deviation of your [NaOH] from the class average value
Part 2 Molar Mass of Unknown Acid - show calculation for one run only Calculate the molar mass of the acid unknown - use the class average value for the [NaOH] equation (3)
Average Molar Mass Of the Unknown Acid - Read the instructions carefully. List all four values from lowest to highest. You may use all four values to calculate the average, or you may use the three closest values. Calculate the range of the three lowest and the range of the three highest. If the ranges are significantly different then use the three with the smallest range, otherwise use all four. Show the range calculations and clearly indicate whether you will be using three or four values to calculate the average and ssd.
Use your calculator to find the average value ( x! ) and sx value (the ssd). The ssd will always have the same units as the average value. You will record the average value twice on the data sheet. Once using the correct SF according to the SF method and once using the ssd to determine the number of SF. x! value ____________
sx value ( the ssd ) ____________
Prelab Exercise
Name
This exercise reviews the calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. a.
A sample weighing 0.3515 g of the primary standard potassium hydrogen phthalate requires 12.42 mL of NaOH solution for neutralization. Calculate the molarity of the NaOH solution.
b.
An organic acid has 2 ionizable hydrogen atoms in the molecule. 0.1548 g of acid is dissolved in water and titrated with the standardized NaOH solution, question a. The final equivalence point is reached after 15.62 mL of the base solution have been added. Calculate the molar mass of the acid.
Student Name Lab Partner Demonstrator Lab Section DATA SHEET Molar Volume of Nitrogen Gas
Marking scheme Prelab exercise Lab performance Sig figs, units Calculations Molar V, Unkn
Part 1 Determination of Molar Volume of N2 (g) Mass of vial and NaNO2 Mass of vial Mass of NaNO2 Moles of NaNO2 Moles of N2 gas Temperature of N2 gas
°C
Temperature of N2 gas
K
Temperature of water
°C
Volume of N2 gas Atmospheric pressure Pressure due to H2O vapour Pressure of N2 (g) alone Volume of N2 (g) corrected to reference conditions L mol!1
Molar volume of N2 (g) Molar volume of an ideal gas at 25°C, 100 kPa % deviation of my measured molar volume from the ideal
24.789 L mol!1
DATA SHEET Molar Volume of Nitrogen Gas Part 2 Determination of mass percent of NaNO2 in Unknown # Mass of vial and Unknown Mass of vial Mass of Unknown Temperature of N2 gas
°C
Temperature of N2 gas
K °C
Temperature of water Volume of N2 gas Atmospheric pressure Pressure due to H2O vapour Pressure of N2 (g) alone Volume of N2 (g) corrected to 25°C and 100 kPa Your Molar Volume of N2 from Part 1 Moles of N2 produced Moles of NaNO2 in sample Mass of NaNO2 in sample % by mass of NaNO2
Average Values for the mass percent of NaNO2 , the two averages below will be the same number but may have different SF Average % by mass of NaNO2 (SF method) Average % by mass of NaNO2
ssd
Additional Calculation - see work sheet Average % by mass of NaNO2
(SF method)
WORK SHEET Part 1 Determination of Molar Volume of N2 (g) Calculate moles of NaNO2 reacted
Calculate pressure of N2 (g) alone, equation (5)
Calculate volume of N2(g) corrected to reference conditions, 298.15 K and 100 kPa, equation (3)
Calculate molar volume of N2(g), equation (4)
Calculate the % deviation of your experimental molar volume from that of an ideal gas, 24.789 L mol!1
Part 2 Determination of NaNO2 content, show calculations for one run only Calculate pressure of N2(g) alone
Calculate volume of N2(g) corrected to reference conditions
Calculate moles of N2 produced
Calculate mass of NaNO2 reacted
Calculate % by mass of NaNO2 in the sample
Average value Write both your % by mass values below and then use your calculator to find the average value ( x! ) and sx value ( the ssd ) for the % by mass of NaNO2 .
x! value
sx value ( the ssd )
You will record the average value twice on the data sheet. Once using the correct SF according to the SF method and once using the ssd to determine the number of SF. Additional Calculation The results for Part 2 could be recalculated using the actual molar volume of N2(g) , 24.777 L mol-1, instead of your molar volume. An easier way to get the same average value is to use the formula given below and your average mass % of NaNO2. Use the value with the SF according to the SF method. Average Mass % of NaNO2 x
Molar Volume (yours) Molar Volume (given)
Prelab Exercise
Name
This exercise reviews the important calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. a. When 0.4853 g of NaNO2 is allowed to react with an excess of sulfamic acid solution, the volume of N2(g) produced is measured by displacement of 163 mL of water. After the reaction is completed, the temperature of water is 26.0°C and that of gas is 24.0°C. The atmospheric pressure is 101.56 kPa. Use equations (3, 4 and 5) to calculate the molar volume of N2 (g) at 25°C and 100 kPa. You may not use PV = nRT.
b. When 0.6087 g of a sample containing NaNO2 and some inert material is allowed to react with an excess of sulfamic acid solution, 128 mL of dry N2 (g) at 25°C and 100 kPa are obtained. Calculate the percentage by mass of NaNO2 in the sample with the aid of the molar volume of N2 (g) at 25°C and 100 kPa from question a.
Student Name
Prelab exercise Lab performance Sig figs, units Calculations Graph pKa, stock conc.
Lab Partner Demonstrator Lab Section DATA SHEET
Spectrophotometric Determination of the pKa of an Indicator tube
HIn
acetic acid
acetate
#
mL
mL
mL
1
10.00
2
10.00
9.00
1.00
3
10.00
8.00
2.00
4
10.00
7.00
3.00
5
10.00
6.00
4.00
6
10.00
5.00
5.00
7
10.00
4.00
6.00
8
10.00
3.00
7.00
9
10.00
2.00
8.00
10
10.00
1.00
9.00
11
10.00
pH absorbance
— 10.00 mL HCl —
— 10.00 mL NaOH —
The pH entries above are calculated in the pre-lab exercise. Model of Spectronic 20 used, analog or digital Indicator concentration, sample tube Indicator concentration, stock solution Calculated absorbance AK for [HIn] = [In2] pKa of bromocresol green Ka of bromocresol green
colour
WORK SHEET Use the absorption constant, ,, for the In2 ion and path length R, given in the strategy and procedure, to calculate the indicator concentration in the sample tube equation (3)
Calculate the indicator concentration in the stock solution - before dilution
Calculate the absorbance AK , for [HIn] = [In2]
equation (4)
Find the pKa of bromocresol green indicator from your graph, read to 2 decimal places, label AK and pKa on the graph. pKa = Ka =
Prelab Exercise
Name
This exercise consists of important calculations required for this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. You will need these data for your graph ! a. Calculate the pH of 10.00 mL of 0.100 M HCl after adding 10.00 mL of indicator solution. Round the pH to three significant figures.
Calculate the pH of 10.00 mL of 0.100 M NaOH after adding 10.00 mL of indicator solution. Round the pH to three significant figures.
b. Calculate the pH of the nine buffer solutions made by mixing 1.10 M acetic acid and 0.900 M sodium acetate solutions according to the following proportions. The pKa for acetic acid, CH3COOH, is 4.745. See Introduction for information on SF and log functions. mL 1.10M HAc
9.00
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
mL 0.900M Ac2
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
pH ( 3 SF ) Show a detailed calculation for one mixture only. The pKa for acetic acid is 4.745.
Student Name Marking scheme Prelab exercise Lab performance Sig figs, units Calculations Graphs Unknown
Lab Partner Demonstrator Lab Section
DATA SHEET Thermochemistry Part 1 Determination of the Heat Capacity of the Calorimeter Mass of calorimeter dry Mass of calorimeter plus cold water Temperature of cold water + calorimeter Temperature of hot water Final mass of calorimeter plus water Mass of cold water Mass of hot water Extrapolated temperature, To
)T for hot water, To ! Thot
K
)T for cold water and calorimeter, To ! Tcold
K
Heat capacity of calorimeter, Ccal The temperature chart and all grey areas must be filled in and checked by the TA before you leave the lab.
DATA SHEET DATA FOR COOLING CURVES (Use ink) TIME min
Part 1 Temp °C
Part 2 Temp °C
Part 3 Temp °C
extra Temp °C
extra Temp °C
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
REMEMBER ! WEIGH THE CALORIMETER AND SOLUTION AT THE END OF EVERY RUN.
DATA SHEET Part 2 The Heat of Neutralization of a Strong Base With a Strong Acid Molarity of standard HCl Final burette reading Initial burette reading Volume of standard HCl used Mass of calorimeter plus final solution Mass of dry calorimeter Mass of final solution Initial temperature of HCl Initial temperature of NaOH Avg temperature of HCl and NaOH, Taverage Extrapolated temperature, To
)T, To – T average Specific heat of NaCl solution, cs Heat absorbed by calorimeter + solution Heat of reaction Moles of H+ reacted
)Hneut Average value of )Hneut
K
DATA SHEET Part 3
Determination of the Concentration of Strong Acid Solution #
Final burette reading Initial burette reading Volume of unknown HCl used Mass of calorimeter plus final solution Mass of dry calorimeter Mass of final solution Initial temperature of HCl solution Initial temperature of NaOH solution Avg temperature of HCl and NaOH, Taverage Extrapolated temperature, To
)T, To – Taverage
K
Specific heat of NaCl solution, cs Heat absorbed by calorimeter and solution Heat of reaction Average Heat of neutralization ( from Part 2 ) Moles of HCl used Molarity of Unknown HCl solution Avg Molarity of Unknown HCl solution
( SF method )
Avg Molarity of Unknown HCl solution
ssd
Additional Calculation Avg Molarity of Unknown HCl solution
( SF method )
(ssd method)
WORK SHEET Part 1 The Heat Capacity of the Calorimeter Calculate the heat capacity of calorimeter equation (4)
If your value of Ccal is negative, check for mathematical errors first, then use Ccal = 0 J K21 in all subsequent calculations. Part 2 The Heat of Neutralization of a Strong Acid With a Strong Base show calculations for one run only Calculate heat absorbed by calorimeter + solution, qabs = [ Ccal ( To – Tavg ) + ms cs ( To – Tavg ) ] = [ Ccal + ms cs] ( To – Tavg ) equation (5)
Heat of reaction = q rxn = Calculate moles of H+ reacted - the limiting reagent
Calculate )Hneut
Write both your values and then calculate the average value of )Hneut,
x! value
equation (6)
Part 3 Determination of the Concentration of Strong Acid Solution show calculations for one run only Calculate heat absorbed by calorimeter + solution, qabs = [ Ccal ( To – Tavg ) + ms cs ( To – Tavg ) ] = [ Ccal + ms cs] ( To – Tavg ) equation (5)
Heat of reaction = q rxn =
equation (6)
Calculate moles of H+ reacted
Calculate molarity of unknown HCl solution
Write both your values here and then calculate average molarity and ssd
x! value
sx value ( the ssd )
Additional Calculation The actual value of the )Hneut is - 55.9 kJ mol!1 . Calculate the molarity of your unknown HCl using this value as follows. Show this calculation. Your average molarity x
)Hneut (yours) )Hneut (given)
Prelab Exercise
Name
This exercise reviews the important calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. a. When 14.28 mL of 2.92 M HCl are added to 15 mL of 3.07 M NaOH, a measurement shows that 2.35 kJ of heat are released. Calculate the heat of neutralization in kJ mol21.
b. Similarly, when 13.98 mL of HCl of unknown concentration (but less than that of the base) are reacted with 15 mL of 3.07 M NaOH, 2.08 kJ of heat are released. From these experimental data, calculate the molarity of the HCl solution.
Student Name
Marking scheme Prelab exercise Lab performance Sig figs, units Calculations
Lab Partner Demonstrator Lab Section
DATA SHEET Redox Titration, a Quantitative Analysis Part 1 Standardization of the KMnO4 Solution Preparation of Na2C2O4 solution Mass of weighing funnel & Na2C2O4 Mass of clean, dry weighing funnel Mass of Na2C2O4 in 100.00 mL solution mol L21
Molarity of Na2C2O4 solution Titration Results
run #
1
Final burette reading Initial burette reading Volume of KMnO4 solution Average volume of KMnO4 used Average molarity of KMnO4
Class average molarity of KMnO4 % deviation of my value from the class average value
2
3
DATA SHEET Redox Titration, a Quantitative Analysis Part 2 Determination of Fe2+ Content in an Iron Supplement Pill Pill #1
#
Pill #2
Pill #3
Mass of powdered pill & boat Mass of empty boat Mass of pill Average molarity of KMnO4 (your own, Part 1) Final burette reading Initial burette reading Volume of KMnO4 solution Moles of KMnO4 Moles of Fe2+ Fe2+ content in pill, mg Moles of FeSO4.7H2O Mass of FeSO4.7H2O Mass % of FeSO4.7H2O Average Mass % of FeSO4.7H2O in pill
(SF method)
Average Mass % of FeSO4.7H2O in pill
ssd
Additional calculation Average Mass % of FeSO4.7H2O in pill
(SF method)
WORK SHEET Part 1 Standardization of the KMnO4 Solution Calculate the molarity of Na2C2O4 solution
Calculate the molarity of KMnO4 solution - a 25.00 mL volume of Na2C2O4 solution was used for every run so the average value of the volume of KMnO4 can be used to find your average [KMnO4]
Calculate % deviation of your average value from Part 1 from the class average value
Part 2 Determination of Fe2+ Content and Mass Percent FeSO4.7H2O in an Iron Supplement Pill, Show calculations for one run only. Use your [KMnO4] value. Calculate moles of permanganate used
Calculate moles of Fe2+
Calculate Fe2+ content in pill in mg
Calculate mass of FeSO4.7H2O in pill, in g
Calculate mass % of FeSO4.7H2O in pill
Write your three values here and then calculate average mass % and ssd of FeSO4.7H2O in pill.
x! value
sx value ( the ssd )
Additional Calculation Calculate the average mass percent of FeSO4.7H2O using the class average [KMnO4 ] as follows. Show this calculation. Average Mass % of FeSO4.7H2O x
[KMnO4 ] (class) [KMnO4 ] (yours)
Prelab Exercise
Name
This exercise reviews the important calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. a.
If 34.86 mL of KMnO4 solution are required to oxidize 25.00 mL of 0.02987 M Na2C2O4 solution, what is the [KMnO4] ?
b.
A certain brand of iron supplement pill contains iron(II) sulphate heptahydrate, FeSO4.7H2O, with miscellaneous binders and fillers. 26.84 mL of the KMnO4 solution used in part a) are needed to oxidize Fe2+ to Fe3+ in a 0.4835 g pill. Calculate the mass % of FeSO4.7H2O (molar mass = 278.0 g mol--1) in the pill.
Lab Partner
Student Name Demonstrator QUALITATIVE ANALYSIS - DATA SHEET
Unknown # _____ ion(s) tested
Colour of Unknown Solution _____________
reagent(s) added
observations for known
observations for unknown
1. Ag+
HCl
2. NH4+
NaOH flame red litmus
what happens to red litmus? <
what happens to red litmus? <
3. Cu2+
1) NaOH
1)
2)
1)
2) NH3
1)
2)
2)
Al3+
1)
2)
Fe2+
1)
Fe3+
1)
Zn2+
interpretation
ion(s) tested
reagent(s) added
4. Na+
observations for known
observations for unknown
< wire or
+
Li
wooden stick
<
flame 2+
<
Cu
5. SO422
<
1) BaCl2
1)
1)
2) HCl
2)
2)
6. NO32
FeSO4 H2SO4
<
<
7. CO322
in large t.t.,
what happens to limewater?
what happens to limewater?
<
<
unknown + HCl
heat in other large t.t., limewater
inter
ion(s) tested
reagent(s) added
8. PO432
(NH4)6Mo7O2
observations for known
observations for unknown
interpretation
4
@4H2O HNO3 heat (if necessary)
9. Cl2
AgNO3
10. Br2
I2
C2HCl3 + chlorine water
colour in the lower layer for Br2 <
colour in the lower layer <
colour in the lower layer for I2 <
Unknown # _____ contains ___________________________________________________________ .
Pre-Lab Exercise
Name
This exercise reviews the reactions associated with this experiment. It must be completed before the laboratory period, and handed in before the pre-lab lecture. JoAnn Student has an Unknown solution that contains iron (III) sulphate. For each ion, state the test(s) that will show a positive result. Write the reaction(s) that will occur for each, including states. a.
iron (III) ion
test number ______
equation
b.
sulphate ion
equation
test number ______
Marking scheme Prelab exercise Lab performance Sig figs, units Calculations Graphs Orders
Student Name Lab Partner Demonstrator Lab Section
Kinetics SUMMARY DATA SHEET
Molarity of the stock potassium iodide solution Molarity of the stock potassium bromate solution Molarity of the stock hydrochloric acid solution
Integral order of the reaction in [BrO32] is Integral order of the reaction in [H+] is Integral order of the reaction in [I2] is Overall order of the reaction is
Average value of the rate constant k,
ssd
(with units) at an average room temperature of
Value of the Activation Energy, Ea is
ssd
K
Table 1: Experimental Data run #
stock
°C
time t s
relative rate 1000 / t mol L!1 s!1
n/a
n/a
n/a
temperature
[BrO32] in flask mol L!1
1 1 avg of run #1
2 3 4 5 6 7 8
t start _____ t finish _____ t avg ______
9
t start _____ t finish _____ t avg ______
10
grey boxes must be filled in before leaving the lab
[H+] in flask mol L!1
[I2] in flask mol L!1
WORK SHEETS Preparation of 0.001000 M Na2S2O3 solution Stock solution molarity Calculate the volume of stock solution required to prepare 250.00 mL of 0.001000 M Na2S2O3 solution.
Determination of the Values for ", $, p and k at room temperature Determination of the value of " run # [BrO32] run #
[BrO32]
relative rate relative rate
Calculate the value of ", the order for [BrO32]
Integral value of "
Value of "
Determination of the value of $, the order for [H+] [H+] relative rate run # run #
[H+]
relative rate
Calculate the value of $
Value of $
Integral value of $
Determination of the value of p , the order of the reaction for [I2] Table 2: [I !] and Relative Rates at Room Temperature run #
[I2] in flask mol L21
log [I2]
relative rate mol L21 s21
log(rate)
Graph log(rate) vs log [I !] and calculate the slope. If graphing by hand show the slope calculation and points used on your graph. Computer generated graphs must have the equation of the line printed on the graph by the computer. Value of p
Integral value of p
Determination of the average value of the rate constant, k Use your integral values for ", $ and p to calculate k for each run, equation (1). Table 3: Concentrations, Relative Rates and k at Room Temperature run #
[BrO32] mol L21
[H+] mol L21
[I2] mol L21
relative rate
temp. K
k
Show one sample calculation of the value of k, and the derivation of the units of k here.
List your values for k and then use your calculator to find the average and ssd.
Average value of k
ssd
units
List your values for the temperature and then use your calculator to find the average and ssd.
at an average temperature
ssd
K
Determination of the Activation Energy, Ea Use your integral values for ", $ and p to calculate k for each run, equation (1). It is not necessary to show this calculation again (see above). Table 4: k Values at Various Temperatures run #
[BrO32] mol L21
[H+] mol L21
[I2] mol L21
relative rate mol L21 s21
k
temp °C
Table 5: Arrhenius Data approx
run #
temp,.°C
actual
1/T
temperature, K
K2
k
ln k
1
5
15
room
use average
35
Graph ln k vs 1/T and calculate the slope. If graphing by hand show the slope calculation and points used on your graph. Computer generated graphs must have the equation of the line printed on the graph by the computer. Slope of the line is Calculate the value of Ea using the slope of your graph
Value of the Activation Energy Ea is
kJ mol21
Prelab Exercise
Name
This exercise reviews some important calculations associated with this experiment. It must be completed before the laboratory period, and handed in before the prelab lecture begins. a)
Which two runs will you use to determine " ?
b)
Which two runs will you use to determine $ ?
c)
Which five runs will you use to determine p ?
d)
For the reaction A ! Products Calculate the value of k and the correct units. [A]
rate
0.040 M
6.25 x 10 !6 mol L!1 s!1
0.080 M
2.50 x 10 !5 mol L!1 s!1