Unit 4: Acids and Bases Flashcards

1
Q

What are some properties of acids?

A

pH<7
Taste sour
Dissolve metals and form hydrogen gas
Conduct electricity (electrolytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some properties of bases?

A

pH>7
Taste bitter
Feel slippery
Conduct electricity (electrolytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does water have to do with acids and bases?

A

They are only acids and bases when dissolved in water. For example, HCl(solid) is just hydrogen chloride (an ionic compound with no acid properties)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some uses of acids?

A

Some batteries.
Stomach acid.
Fertilizers.
Petroleum production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some uses of bases?

A

Cleaning products
Soap
Medicine (like antacids)
Water treatment
Cement, mortar, and plaster.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you write the dissociation of acids and bases?

A

On the left, write the acid/base. On the right, write it broken apart into its ions. Remember that dissociation is reversible so double arrows must be used. Remember to write the physical states and charges.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two theories of acids and bases?

A

The Arrhenius theory of acids and bases.
The Bronstead/Lowry theory of acids and bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Arrhenius theory of acids and bases?

A

Svante Arrhenius discovered that the properties of acids and bases were caused by H+ ions and OH- ions when dissolved in water.
Both acids and bases dissolve in water to form ions. Water is usually not included, although there is evidence to show that H3O+ (hydronium) is produced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Bronstead/Lowry theory of acids and bases?

A

The noticed that some bases have not OH- ions.
Acids are compounds that donate a proton.
Bases are compounds that accept a proton.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are conjugate acids/bases

A

In the reverse direction by the Bronstead/Lowry theory, acids become bases and bases become acids (conjugates).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an amphoteric substance?

A

A substance that can act as an acid in one reaction and a base in another. Such as HSO4.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a polyprotic acid?

A

An acid that can donate more than one hydrogen ion. The first H+ ion is the easiest to remove. Subsequent H+ ions are more difficult to remove because the compound gains a negative charge.
For example: H3C6H5O7 can lose 3 hydrogen ions. This means it has three dissolving reactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a strong acid?

A

An acid that dissolves completely in H2O and produces a high concentration of H+ ions. Strong bases are the same but with OH- ions instead of H+ ions. They are strong electrolytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are weak acids?

A

They dissolve poorly in H2O and produce a low concentration of H+ ions. Weak bases are the same but with OH- ions instead of H+ ions. They are weak electrolytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are ionization constants?

A

Because acid/base solutions are systems at equilibrium, we can write an equilibrium expression and solve for the equilibrium constant.
Ka: acid equilibrium constant
Kb: base equilibrium constant
Kw: Water equilibrium constant

Write the equations as normal equilibrium constant equations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do you use an ionization constant to determine which side is favoured?

A

Ka>1: products favoured (strong acid)
Ka<1: reactants favoured (weak acid)
Same for Kb.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Does water ionize?

A

Yes, but not well. It produces H+ and OH- ions. In pure neutral water, [H+]=1.0x10^-7 and [OH-]=1.0x10^-7.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is [H+][OH-] in water?

A

Always 1.0x10^-14

19
Q

How do you tell how much H+/OH- ions an acid/base will make when dissolved?

A

If strong, they fully dissolve and correlate directly to their reactants. Ex: if HCl is a strong acid and one mole is dissolved in 1 liter of water, HCl -> 1H+ + 1Cl- : 1 mole of H+ ions is produced

If weak, use the kb/ka and occassionally the kw to find the OH-/H+ ions.

20
Q

What does pH stand for?

A

Potenz of the hydrogen ion

21
Q

What do the pH values indicate?

A

pH<7: acidic
pH>7: basic
pH=7: neutral

22
Q

What scale does pH use?

A

The logarithmic scale. An increase/decrease of 1 pH is 10x the concentration.

23
Q

What is pOH?

A

pOH is pH but measuring OH-. pOH+pH is always 14. This can be used to simplify questions.

24
Q

How do you calculate pH?

A

Take the negative log of the concentration of H+

pH=-log([H+])
You can reverse this (find [H+] from pH) with [H+]=10^-pH

25
Q

Conjugate base/acid pairs differ by…

A

A single proton (hydrogen ion)

26
Q

What are Ka, Kb, and Kw?

A

The acid, base, and water equilibrium constants

27
Q

Difference in meanings between [H+] and Ka? (Or base equivalent)

A

[H+] > 1.0x10^-7M is acid
= 1.0x10^-7 is neutral
< 1.0x10^-7 is basic
Replace acid with base and base with acid for [OH-].

Ka just refers to the strength of the acid. (Kb refers to strength of base)

28
Q

For Ka and Kb, how do you tell whether or not something is a strong acid/base?

A

If kb/ka > 1 : strong base/acid
If kb/ka < 1: weak base/acid

29
Q

You are given a compound and asked to find its conjugate acid. How is this done?

A

Add 1 hydrogen and increase the charge by one

Do the opposite for conjugate bases

30
Q

Rule of 1000

A

If you divide the initial concentration by the kps and the product is more than 1000, the change is negligible, relative to the concentration and you can omit the change to simplify the equation.

Ex. 0.5M weak acid changes by x. Ka is k. 0.5M/k… if the result is greater than 1000, the change is negligible

31
Q

What is titration?

A

When equal moles of a strong acid and strong base are mixed together, they neutralize each other (pH=7) to form water and an ionic compound.

32
Q

Weak base and strong acid mixed together (equal amounts), what happens?

A

Slightly acidic. And vice versa.

33
Q

How can you use titration to determine the concentration of an acid/base?

A

If one is known, you can calculate the concentration of the unknown. Use CaVa=CbVb

34
Q

How do you mark the equivalence point in titration?

A

You use an indicator.

35
Q

Titration calculation formula

A

(Ca)(Va)(nb)=(Cb)(Vb)(na) Remember to balance your equations. na and nb are the coefficients of the acids and bases in the balanced reaction.

36
Q

What should you do before any equation?

A

Balance! Always balance!

37
Q

What should you remember about keq equations?

A

Remember balanced equations when solving, squares and multiples, etc

38
Q

What should you remember about the rule of 1000?

A

It is relative. x change alone is relevant. N+-x, x may be negligible.

Initial concentration over ksp

39
Q

ICE calculations, what should you remember?

A

BALANCE. Remember double arrows

40
Q

What are indicators?

A

Dyes that change colour under varying pH levels

41
Q

Difference between titration and neutralization

A

Titration involves a known concentration in neutralization

Neutralization is just that

42
Q

What is a standard solution?

A

A solution with known concentration

43
Q

What is the equivalence point

A

The point at which the solution is neutral