CHM135H1 Lecture Notes - Lecture 19: Conjugate Acid, Lone Pair, Hydronium

19 views4 pages

greymallard552

29 Oct 2016

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

avalack09 and 39671 others unlocked

CHM135H1 Full Course Notes

Verified Note

90 documents

Document Summary

Chm135h1 f - lecture 19 - chapter 14 (4) Classifies acids and bases in terms of their behavior in water. Acid has h in its formula that dissociates into h+ (h3o+: general equation: ha (aq) h+ (aq) + a- (aq) Base has oh in its formula that dissociates into oh: general equation: moh (aq) m+ (aq) + oh- (aq) Neutralization: reaction between acid and base: general equation: h+ (aq) + oh- (aq) -> h2o (l, note that this reaction is highly exothermic ( h rxn = 55. 9 kj/mol), and is not at equilibrium. Acid is proton donor (donates h+ ion) - therefore must have an h in its formula. Base is proton acceptor (accepts h+ ion) - must contain at least one lone pair of electrons to bond to accepted proton, though does not necessarily have oh in its formula.

Related Questions

Observations In columns 3 and 4, record the color and intensity seen. In columns 5 and 6, determine if the substance is an acid or a base, and if the substance is ionic. For the last column, determine which chemical species is acting as an acid or base.

Data Table 1: Acids and Bases Acting in Water
Well	Substance	1drop BTB	Plus 1 drop of substance	Acid or base (Q1)	Ionic? Y/N (Q2)	Species acting as acid or base (Q3)
1	NaHCO3
2	CH3COOH
3	HCL
4	Na2CO3
5	H2SO4
6	CH3COONa
7	NaOH
8	HNO3
9	NaHSO4
10	NH3
11	H3PO4
12	NaH2PO4
13	Na2HPO4
14	Na3PO4
15	NaHSO3

Data Table 2: Following Acid/Base neutralization reactions
Well #	1 Drop of Each	Observation	+2 Drops Acid	Observation	+2 Drops Base	Observation
1	BPB + NaOH		HCl		NaOH
2	BPB + NaOH		H2SO4		NaOH
3	BPB + NaOH		CH3COOH		NaOH
4	BPB + NaOH		H3PO4		NaOH
5	BPB + Ca(OH)2		HCl		Ca(OH)2
6	BPB + Ca(OH)2		H2SO4		Ca(OH)2
7	BPB + Ca(OH)2		CH3COOH		Ca(OH)2
8	BPB + Ca(OH)2		H3PO4		Ca(OH)2
9	BPB + NH3		HCl		NH3
10	BPB + NH3		H2SO4		NH3
11	BPB + NH3		CH3COOH		NH3
12	BPB + NH3		H3PO4		NH3

Please note here if any of the other starting materials is other than a clear, colorless solution.

Data Table 3: Investigating Odor as a Means of Indicating Neutralization.
Substance(s)	Odor
2 Drops of HCl in Well #1
1 Drop of Ammonia on Swab
Swab with Ammonia & HCl

Data Table 4: Investigating Evaporation as a Means of Indicating a Neutralization Reaction.
Reaction Mixture	Observation (When Wet)	Observation (When Dry)
HCl + NaOH
CH3COOH + NH3
HNO3 + NaOH

PART 5: Mini-Experiments

1. Use BTB to classify four household products as acidic or basic. Possible substances to test include home cleaning products, glass cleaner, liquid detergent, bleach, soft drinks, liquid from food items, etc. Remember to:

a. Hypothesis (What you think will happen and why) or purpose:

b. Method used to test your hypothesis:

c. Data and Observations Put your data and observations in the space below. You can include pictures that you âdraw.â

d. Conclusions

2. Find one common, highly colored substance that can be used as an acid-base indicator.

Possible substances include fruit/vegetable juice or products, inks, food coloring, flower

petals, etc. If using fresh fruit, veggies, or flowers, crush the substance with a little water or

rubbing alcohol to extract the colored pigments. If red cabbage is available, it makes a superb

acid-base indicator. Then use a few drops of the colored extract as the indicator. Test four

more household products using the freshly made acid-base indicator. Remember to:

a. State a hypothesis or purpose.

b. State the testing method.

c. Use the prepared indicator to test four substances known to be acids or bases from either the LabPaq or home materials and record results.

d. State conclusions in terms of the hypothesis or purpose.

Questions

A. Review the substances used in Part 1. Determine whether each substance contains an acid or a base based on the BTB results. Place answers to this question in column 6 of Data Table 1.

B. Review the responses to Question 3. The anion that is produced in the dissociation of the compound goes on to react with the water. Identify the anion product in each reaction. Place the formulas for these species into column 7 of Data Table 1. If the substance is not ionic and thus does not dissociate, then list the substance in column 7, just as it appears in column 1.

C. For each ionic species in Data Table 1, write the equation showing the dissociation of the compound in water. Hint: thereâs one for each line provided below.

a. NaHCO3 Ã Na

+ HCO3

Review the responses to Question 3. The anion that is produced in the dissociation of the compound goes on to react with the water. Identify the anion product in each reaction. Place the formulas for these species into column 7 of Data Table 1. If the substance is not ionic and thus does not dissociate, then list the substance in column 7, just as it appears in column 1.

D. Write the reaction of each acid or base the substance listed in column 7 with water.

Acids: Bases:

a) HCO - + H-OH Ã H CO

+ OH-

3 2 3

1. What is produced in each and every reaction of an acid with water?

2. What is produced in each and every reaction of a base with water?

E. Review the results in Data Table 2. For each reaction mixture, write the reaction equation describing the acid/base neutralization reaction:

2) 2NaOH + H2SO4 Ã 2H2O + Na2SO4

F. Define the term âneutralizationâ and provide an example of a neutralization equation. List the three ways used in this lab to detected neutralization.

G. Define the term âsalt,â and provide an example.

H. Review Data Table 3. What happened when the two chemicals were mixed? What indicates that conclusion? What reaction took place?

I. Review Data Table 4. What happened when the solution mixtures on the glass slide were heated? Describe the process that took place.

J. In Part 4, for HCl + NaOH, what is left on the slide after heating? Provide the formula. What is the common name of this substance?

QUESTION 1

Which of the following substances is most acidic?

		Cowâs milk - pH 6.6
		Apple juice - pH 3.0
		Tomato juice - pH 4.5
		Distilled water - pH 7.0

2 points

QUESTION 2

A buffer is a substance that converts:

Alkaline solutions to neutral solutions.

Acidic solutions to alkaline solutions.

Strong bases or acids to weak bases or acids.

Acidic solutions to neutral solutions.

QUESTION 3

How does a solution of pH 7 compare to a solution of pH 10?

		pH 7 has more OH^- ions
		pH 7 is more basic
		pH 7 has a higher pH
		pH 7 has more H⁺ ions

2 points

QUESTION 4

According to the Arrhenius Theory of acids and bases, a base is:

A substance that decrease the amount of hydroxide ions present.

A substance that increases the amount of hydroxide ions present when it is dissolved in water.

A substance that increase the amount of hydrogen ions present.

A substance that increases the amount of hydrogen ions present when it is dissolved in water.

QUESTION 5

Which of the following are true regarding acid-base titrations?

		They are used to determine the concentration of an unknown acid or base.
		The acid or the base must be a standard solution with a known concentration
		The standard solution is titrated into the chemical with the unknown concentration.
		All of the above are true regarding acid-base titrations.

2 points

QUESTION 6

Which of the following is not an example of a neutralization reaction?

HCl + NaOH NaCl +H₂O

2 NaOH + H₂CO₃ Na₂CO₃ +2 H₂O

H₂SO₄ + 2 NH₄OH (NH₄)₂SO₄ + 2 H₂O

2 AgNO₃ + Zn 2Ag +Zn(NO₃)₂

QUESTION 7

Which acid base theory defines an acid as a proton donor and a base as a proton acceptor?

		Arrhenius Theory
		Bronsted-Lowery Theory
		Conjugate Pairs Theory
		Lewis Theory

2 points

QUESTION 8

The Arrhenius Theory states that acid-base reactions create a solution composed of a water and a salt. This is because mixing an acidic and basic solution together yields:

A neutral solution

A solution with a pH at or near 7

Both A and B are correct

QUESTION 9

Which of the following correctly defines a standard solution?

		A solution which always has the same molecular geometry.
		A solution in which the concentration is precisely known.
		A solution in which the volume is precisely known.
		A solution which always has different levels of solutes and solvents.

2 points

QUESTION 10

Acids naturally present in food are generally safe to eat because they are usually:

		Concentrated
		Dilute
		Weak
		Strong

None of the above are correct

CHM135H1 Lecture Notes - Lecture 19: Conjugate Acid, Lone Pair, Hydronium

CHM135H1 Full Course Notes

Document Summary

Get access

Related Documents

CHM135H1 Lecture Notes - Lecture 21: Benzoic Acid, Sodium Hydroxide, Potassium Perchlorate

CHM135H1 Chapter Notes - Chapter 16: Weak Base, Acid Strength, Chemical Equation

CHM135H1 Chapter Notes - Chapter 15: Ph, Ph Meter, Conjugate Acid

Related Questions