Lab 05 - Determining the Molar Mass of an Acid Report TB Typed 2023 copy
docx
keyboard_arrow_up
School
Raritan Valley Community College *
*We aren’t endorsed by this school
Course
104
Subject
Chemistry
Date
Feb 20, 2024
Type
docx
Pages
7
Uploaded by GeneralStrawWren57
Lab 05 - Determining the Molar Mass
of an Acid
Determining the Molar Mass of an Unknown
Report DATA
Standardization of sodium hydroxide solution
KH C
8
H
4
O
4
(
aq
)
+
NaOH
(
aq
)
→ KNaC
8
H
4
O
4
(
aq
)
+
H
2
O
(
l
)
Fill in the table (18 pts). Show all calculations in your lab notebook. 5 pts
Trial 1
Trial 2
Mass of KHC
8
H
4
O
4
(g)
0.256 g 0.251 g
Molar mass of KHC
8
H
4
O
4
(g/mol)
204.2
204.2
Moles of KHC
8
H
4
O
4
(mol) (Use 6 significant figures)
0.00125 mol
0.00122 mol
Initial level of NaOH (mL)
0.00 mL
12.80 mL
Final level of NaOH (mL)
12.50 mL
24.70 mL
Volume of NaOH used in titration (mL)
12.50 mL
11.9 mL
Moles of NaOH (mol) (Use 6 significant figures)
0.00125 mol
0.00122 mol
Your molarity for NaOH (M)
(Use 6 significant figures)
0.100 M
0.103 M
Average for molarity NaOH (M) (Use 3 significant figures)
0.101 M
1
2
Determination of the molar mass of an unknown acid.
Type of acid (circle): H
2
A
or H
3
A or
H
2
A
.
H
2
O
H
2
A
(
aq
)
+
2
NaOH
(
aq
)
⇌
N a
2
A
(
aq
)
+
2
H
2
O
(
l
)
or
H
2
A .
2
H
2
O
(
aq
)
+
2
NaOH
(
aq
)
⇌
N a
2
A
(
aq
)
+
4
H
2
O
(
l
)
or
H
3
A
(
aq
)
+
3
NaOH
(
aq
)
⇌
N a
3
A
(
aq
)
+
3
H
2
O
(
l
)
Fill in the table (20 pts). Show all calculations in your lab notebook. 5 pts
Trial 1
Trial 2
Mass of acid sample (g)
0.199 g
0.199 g
Initial level of NaOH (mL)
1.69 mL
1.65 mL
Final level of NaOH (mL)
29.5 mL
31.9 mL
Volume of NaOH dispensed (mL)
27.9 mL
30.25 mL
Average Molarity of NaOH (M) (Use 3 significant figures)
0.101 M
0.101 M
Moles of NaOH used (mol) (Use 6 significant figures)
0.00281790 mol
0.00305525 mol
Moles of acid sample (mol) (Use 6 significant figures)
0.00140895 mol
0.00152763 mol
Molar mass of unknown acid (g/mol)
(Use 6 significant figures)
141.240 g/mol
130.267 g/mol
Average molar mass of acid (g/mol)
(Use 3 significant figures)
136 g/mol
Percent error
10.37%
3
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
(Use 3 significant figures)
Actual values: H
2
A = 118 g/mol, H
2
A
.
H
2
O = s, H
3
A = 192 g/mol
5 points for accuracy
DATA ANALYSIS
Laboratory Questions 1.
Discuss the accuracy
of your results
for the molar mass of the unknown acid
. Indicate what your discussion is based on. (3 pts)
Our percent error was 10.37% which means that the accuracy of our results was okay, but improvement is possible. This error could have been the result of not transferring all of the unknown acid into the volumetric flask.
2.
Sodium hydroxide is hygroscopic
, which is why we keep the bottle of sodium hydroxide covered to prevent contact with air. Define
the term in bold and explain
the specific error that would occur if you used the mass of NaOH to determine the molarity of the solution instead of standardizing the solution. Clearly indicate whether the error will lead to a calculated molarity that is too high or too low. (3 pts)
When a substance is hygroscopic, it can adsorb and absorb moisture from the surrounding environment. If I used the mass of NaOH to determine the molarity of the solution instead of standardizing the solution, the actual sodium hydroxide quantity will be less due to moisture present in the substance. The error would lead to a lower calculated molarity. 3.
Carbon dioxide slowly reacts with water over time, as shown in the equation below. How does this affect the molarity of the NaOH solution over time? Be specific and include a chemical equation to support your answer. (4 pts)
C O
2
(
g
)
+
H
2
O
(
l
)
⇌
H
2
C O
3
(
aq
)
Carbon dioxide dissolves in water to form carbonic acid. H
2
C O
3
neutralizes some of the basic NaOH solution to form sodium carbonate. The molarity of the NaOH solution will decrease over time.
4
2
NaOH
(
aq
)
+
H
2
CO
3
(
aq
)
→Na
2
CO
3
(
aq
)+
2
H
2
O
(
l
)
5
4.
A student does not remove the air bubble from the tip of the burette before standardizing the NaOH solution. How does this mistake affect her recorded results? Indicate whether each data point increases
(I), decreases (D), or does not change (NC). (8 pts)
I / D / NC
Mass of KHC
8
H
4
O
4
(g)
NC
Molar mass of KHC
8
H
4
O
4
(g/mol)
NC
Moles of KHC
8
H
4
O
4
(mol)
NC
Initial level of NaOH (mL)
NC
Final level of NaOH (mL)
I
Volume of NaOH used in titration (mL)
I
Moles of NaOH (mol)
NC
Your molarity for NaOH (M)
D
5.
A student does not transfer all of the unknown acid into the flask before titrating with an NaOH solution that was correctly standardized. How does this mistake affect his recorded results? Indicate whether each data point increases (I), decreases (D), or does not change (NC). (8 pts)
I / D / NC
Mass of acid sample (g)
D
Initial level of NaOH (mL)
NC
Final level of NaOH (mL)
NC
Volume of NaOH dispensed (mL)
NC
Molarity of NaOH (M)
NC
Moles of NaOH used (mol)
NC
Moles of acid sample (mol)
NC
Molar mass of unknown acid (g/mol)
D
6
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
SUMMARY
Provide a brief summary (one or two paragraphs) that describes what you did during the experiment (i.e. the method, not a procedure), what you determined from completing the experiment (i.e. results), and the validity
of your results (i.e. accuracy and precision). (6 pt)
In this experiment, we determined the standardization of a sodium hydroxide solution and the molar mass of an unknown acid. For Part A, we found that the average molarity for NaOH was 101 M. For Part B, we found that the average molar mass of the unknown acid was 136 g/mol. This was somewhat greater compared
to the actual value of 123 g/mol. Our percent error was 10.37% which means that the accuracy of our results was okay, but improvement is possible. Such a high value could have stemmed from errors in the volume of the erlenmeyer flask we used. For example, we may have not transferred all of the unknown acid into the flask with the deionized water, not added enough water, or not added enough of phenolphthalein, the acid-base indicator. Type all answers then print, attach signed Prelab to the front
, and carbon copy to the back
.
7
Related Documents
Related Questions
You dilute the river water 10 times for the analysis of SDS concentration. The instrument measures
an average molar concentration of SDS in the diluted river water to be 1.689 10-4 mol/L. The
molar mass of SDS is 288.4 g/mol.
What is the mass concentration of SDS in the original river water?
4.87 10-1 g/L
4.87 102 g/L
5.86 106 g/L
5.86 10-5 g/L
arrow_forward
+ Chemistry 20 Midterm Equation Sheet (Click to open)
Nitric acid is a potentially dangerous strong acid that must be handled with great care. A laboratory technician is asked to dilute a sufficient quantity of stock 15.4 mol/L nitric acid to produce
1.50 L of a 0.220 mol/L solution. Calculate the volume of concentrated nitric acid needed to prepare this diluted solution.
XQ
F1
BI E E
F2
2 E
E
F3
%
F4
F5
U S
X₂
x²
E
F6
II Proctorio is sharing your screen.
Ⓡ
F7
= I
Stop sharing
DO LL
F8
5 C
H
Hide
+
F9
✓
C
F10
arrow_forward
Fill in the blanks.
Calculate the Average molarity (M) of Acetic acid in vinegar, using the following data.
Calculate the mass percent of acetic acid in vinegar, using your average Acetic acid concentration (M) from the above result.
Table 2. Data for titration of 20.00 mL of vinegar with approximately 1.2 M NaOH.
arrow_forward
Data Analysis and Interpretation
1. Marble is calcium carbonate, CaCO3. Its reaction with hydrochloric acid is
CaCO3(s)+ 2HC1(aq) → CaCl2(?)+ CO2(g) + H2O(!)
What was the gas produced when marble reacted with HC1? Using the solubility rules, determine the
physical state for CaCl2, explain which rule you used.
id
Do these
arrow_forward
Please answer A&B from both questions.
[cu2+]= 7.5x10^-35 is INCORRECT
[OH-]= 4.32x10^-7 is INCORRECT
please show how to get correct answers.
Thank you!
arrow_forward
www-awn.aleks.com
CHEMICAL REACTIONS
Brittney V
Using molarity to find solute mass and solution volume
Calculate the volume in milliliters of a 2.0 mol/L nickel(II) chloride solution that contains 200. g of nickel(II) chloride (NiCl,). Round your answer to 2
significant digits.
|mL
х10
Ar
Explanation
Check
© 2021 McGraw-Hill Education. All Rights Reserved.
Terms of Use | Privacy | Accessibility
arrow_forward
Please answer Parts 2 and 3
arrow_forward
What volume in
L of a 0.32M Mg(NO:)2 solution contains 45
g of Mg(NO:): ?
X
STARTING AMOUNT
ADD FACTOR
ANSWER
RESET
*( )
148.33
86.32
10
45
1
210.34
6.022 x 1023
0.097
0.95
0.32
140
0.30
L
mL
mol Mg(NOs): M Mg(NOs):
g Mg(NOs)2 g Mg(NO:)»/mol
arrow_forward
Part 1 of 2
Determine the pH of a 0.30 M NH3 solution. Be sure your answer has the correct number of significant digits.
-5
Note: K for NH₂ is 1.78 × 10¯
pH =
x10
X
S
arrow_forward
STARTING AMOUNT
X
ADD FACTOR
x( )
0.700
g/mL
Convert the concentration of 0.700 M Na₂SO to g/mL
6.022 x 1023
M Na₂SO
2
1000
mL
Question 23 of 24
1
83.3
119.05
g Na+
ANSWER
0.001
mol Na+
142.04
0.0833
g Na₂SO
2
0.0994
L
RESET
3
99.4
mol Na₂SO
Submit
+
arrow_forward
A Chem 1B student has to prepare 155 mL of 0.100 M KI in water. He finds a bottle that states it is 10.00% KI in water and has a density of 1.07 g/mL. He takes 1.55 mL of the 10.00 % solution and dilutes it to a final volume of 155 mL. Support your answers with correct calculations.a) What is the concentration of the solution he prepared?
arrow_forward
2. Choose the correct answer and show the step by step solution.
arrow_forward
How many grams of nitric acid , HNO3, are required to neutralize (completely react
with) 4.30 |g of Ca(OH)2 according to the acid-base reaction:
2
HNO3(aq) + Ca(OH)2(aq) –
2 H20(1) + Ca(NO3)2(aq)
STARTING AMOUNT
ADD FACTOR
ANSWER
RESET
*( )
1
6.022 x 1023
0.116
74.10
164.10
0.0580
4.30
0.0682
3.60
18.02
7.31
63.02
|g Ca(ОН)2
mol HNO3
g Ca(NO3)2
mol H20
g HNO3
g H20
mol Ca(NO3)2
mol Ca(OH)2
App Store
arrow_forward
STARTING AMOUNT
+
X
mL
ADD FACTOR
x( )
0.700
0.0833
g Nat
Convert the concentration of 0.700 M Na SO to g/mL
0.01
1
6.022 x 1023
g Na₂SO
119.05
L
100
142.04
ANSWER
0.001
99.4
0.0868
1000
RESET
2
0.0994
83.3
g/mL M Na₂SO mol Na₂SO
mol Na
arrow_forward
Sample 1
Sample 2
Sample 3
Mass of Erlenmeyer Flask (g)
24.33
24.37
24.44
Mass of Erlenmeyer Flask + Calcium Hydroxide Solution (g)
(g)(lime water)
27.22
27.29
27.33
Mass of Calcium Hydroxide Solution (g)
2.89
2.92
2.89
Volume of Ca(OH)2
Density = 1.000 g/mL
2.89
2.92
2.89
Concentration of HCl (M)
0.1
0.1
0.1
Initial HCl Volume in Syringe (mL)
1.00+1.00
1.00+1.00
1.00+1.00
Final HCl Volume in Syringe (mL)
.72
.66
.54
Volume of HCl Delivered (mL)
1.28
1.34
1.46
Moles of HCl Delivered
Moles of OH- in Sample
Moles of Ca2+ in Sample
Molar Solubility (M)
Calculated Ksp
Average Calculated Ksp
Hello, I need to know how to actually solve each one because I will need to show my work.
arrow_forward
A student takes a sample of KOH solution and dilutes it to 100.00 mL of water. The student determines that the diluted solution is 0.024 M KOH, but has forgotten to record the volume of the original sample. The concentration of the original solution is 3.685 M. What was the volume of the original sample (in mL)?
Answer to 2 decimal places
Read about significant figures and rounding in the Helpful Resources page!
Do not include units when reporting your answer
Use standard notation or scientific notation as accepted by blackboard
e.g. 0.001 or 1E-3, not 1 x 10^-3
arrow_forward
Sample 1
Sample 2
Sample 3
Mass of Erlenmeyer Flask (g)
24.33
24.37
24.44
Mass of Erlenmeyer Flask + Calcium Hydroxide Solution (g)
(g)(lime water)
27.22
27.29
27.33
Mass of Calcium Hydroxide Solution (g)
2.89
2.92
2.89
Volume of Ca(OH)2
Density = 1.000 g/mL
2.89
2.92
2.89
Concentration of HCl (M)
0.1
0.1
0.1
Initial HCl Volume in Syringe (mL)
1.00+1.00
1.00+1.00
1.00+1.00
Final HCl Volume in Syringe (mL)
.72
.66
.54
Volume of HCl Delivered (mL)
1.28
1.34
1.46
Moles of HCl Delivered
Moles of OH- in Sample
Moles of Ca2+ in Sample
Molar Solubility (M)
Calculated Ksp
Average Calculated Ksp
I am very confused how to solve the blank spots in the table. Everything including and after "Moles of HCl Delivered" confuses me. Please help me figure out how to solve the sections correctly. Also feel free to…
arrow_forward
A solution is prepared by dissolving 4.40 g of KSCN in enough water to make 340. mL of solution. What is the concentration (molarity) of the solution?
For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac).
BIUS Paragraph
v Arial
EX² X₂
¶ ¶<
+₁
V 10pt
√
¶T
E v
田く
T
HH
26
arrow_forward
SEE MORE QUESTIONS
Recommended textbooks for you
Chemistry: The Molecular Science
Chemistry
ISBN:9781285199047
Author:John W. Moore, Conrad L. Stanitski
Publisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781337399074
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781133949640
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Introductory Chemistry: A Foundation
Chemistry
ISBN:9781337399425
Author:Steven S. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Related Questions
- You dilute the river water 10 times for the analysis of SDS concentration. The instrument measures an average molar concentration of SDS in the diluted river water to be 1.689 10-4 mol/L. The molar mass of SDS is 288.4 g/mol. What is the mass concentration of SDS in the original river water? 4.87 10-1 g/L 4.87 102 g/L 5.86 106 g/L 5.86 10-5 g/Larrow_forward+ Chemistry 20 Midterm Equation Sheet (Click to open) Nitric acid is a potentially dangerous strong acid that must be handled with great care. A laboratory technician is asked to dilute a sufficient quantity of stock 15.4 mol/L nitric acid to produce 1.50 L of a 0.220 mol/L solution. Calculate the volume of concentrated nitric acid needed to prepare this diluted solution. XQ F1 BI E E F2 2 E E F3 % F4 F5 U S X₂ x² E F6 II Proctorio is sharing your screen. Ⓡ F7 = I Stop sharing DO LL F8 5 C H Hide + F9 ✓ C F10arrow_forwardFill in the blanks. Calculate the Average molarity (M) of Acetic acid in vinegar, using the following data. Calculate the mass percent of acetic acid in vinegar, using your average Acetic acid concentration (M) from the above result. Table 2. Data for titration of 20.00 mL of vinegar with approximately 1.2 M NaOH.arrow_forward
- Data Analysis and Interpretation 1. Marble is calcium carbonate, CaCO3. Its reaction with hydrochloric acid is CaCO3(s)+ 2HC1(aq) → CaCl2(?)+ CO2(g) + H2O(!) What was the gas produced when marble reacted with HC1? Using the solubility rules, determine the physical state for CaCl2, explain which rule you used. id Do thesearrow_forwardPlease answer A&B from both questions. [cu2+]= 7.5x10^-35 is INCORRECT [OH-]= 4.32x10^-7 is INCORRECT please show how to get correct answers. Thank you!arrow_forwardwww-awn.aleks.com CHEMICAL REACTIONS Brittney V Using molarity to find solute mass and solution volume Calculate the volume in milliliters of a 2.0 mol/L nickel(II) chloride solution that contains 200. g of nickel(II) chloride (NiCl,). Round your answer to 2 significant digits. |mL х10 Ar Explanation Check © 2021 McGraw-Hill Education. All Rights Reserved. Terms of Use | Privacy | Accessibilityarrow_forward
- Please answer Parts 2 and 3arrow_forwardWhat volume in L of a 0.32M Mg(NO:)2 solution contains 45 g of Mg(NO:): ? X STARTING AMOUNT ADD FACTOR ANSWER RESET *( ) 148.33 86.32 10 45 1 210.34 6.022 x 1023 0.097 0.95 0.32 140 0.30 L mL mol Mg(NOs): M Mg(NOs): g Mg(NOs)2 g Mg(NO:)»/molarrow_forwardPart 1 of 2 Determine the pH of a 0.30 M NH3 solution. Be sure your answer has the correct number of significant digits. -5 Note: K for NH₂ is 1.78 × 10¯ pH = x10 X Sarrow_forward
- STARTING AMOUNT X ADD FACTOR x( ) 0.700 g/mL Convert the concentration of 0.700 M Na₂SO to g/mL 6.022 x 1023 M Na₂SO 2 1000 mL Question 23 of 24 1 83.3 119.05 g Na+ ANSWER 0.001 mol Na+ 142.04 0.0833 g Na₂SO 2 0.0994 L RESET 3 99.4 mol Na₂SO Submit +arrow_forwardA Chem 1B student has to prepare 155 mL of 0.100 M KI in water. He finds a bottle that states it is 10.00% KI in water and has a density of 1.07 g/mL. He takes 1.55 mL of the 10.00 % solution and dilutes it to a final volume of 155 mL. Support your answers with correct calculations.a) What is the concentration of the solution he prepared?arrow_forward2. Choose the correct answer and show the step by step solution.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Chemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
- Introductory Chemistry: A FoundationChemistryISBN:9781337399425Author:Steven S. Zumdahl, Donald J. DeCostePublisher:Cengage Learning
Chemistry: The Molecular Science
Chemistry
ISBN:9781285199047
Author:John W. Moore, Conrad L. Stanitski
Publisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781337399074
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781133949640
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Introductory Chemistry: A Foundation
Chemistry
ISBN:9781337399425
Author:Steven S. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning