E X A M I I

pH, conjugates♥

200

Conjugate base of H₂X

HX

400

pH of a .20M solution of KCN (K_a = 6.2 x 10^-10)

11.25

600

If I put equal amounts (in mols, not molarities) of a strong monoprotic acid and a strong monoprotic base in water, does the pH have to be 7?

Yes, each mol makes 1 H and 1 OH which neutralize.

800

J, L and M are in the same column, rank the following strengths

H₂JO2, H₂JO₄, H₂JO₃

H₂JO₄ > H₂JO₃ > H₂JO₂

1000

for H₂SeO₄ 

K_a1 = Very Large

K_a2 = 2.2 x 10^-2

Rank H₃O⁺, SeO₄​^2-​​​ HSeO₄^-, and H₂SeO₄

SeO₄^2- < HSeO₄ < H₃O⁺

Buffers♦

200

Does a buffer increase pH, decrease pH, or can do either?

Can do either depending on whether you put an acid or base in

400

Which of the following will make a buffer? (Can choose multiple)

HI and NaI

HClO₄ and NaClO₄

HNO₂ and NaNO₂

HNO₂ and NaNO₂

600

Which would neutralize 50 mL of .15M NaOH without undergoing a large pH change? (Can choose multiple)

40 mL .10M HF & .30M NaF

25 mL of .20M HC₃H₂N₃O₃ and .10M NaC₃H₂N₃O₃

30 mL of .25M HIO and .20M NaIO

30 mL of .25M HIO and .20M NaIO

Others o not have enough mmols to neutralize without being neutralized

800

pH of the buffer of 

100mL of .25M KNO₂ and    

80mL of .40M HNO₂             

K_a HNO₂ = 7.1 x 10^-4

Using Henderson Hasselbach

pH = 3.04

1000

Can a H₂SO₄ form a buffer?

Yes, HSO₄^- can reach equilibrium with HSO₄^2-

‼Careful‼

200

Conjugate base of H₃O⁺

Water (H₂O)

400

Will putting the conjugate acid of a polyprotic acid in water make it more acidic or basic or depends? (Be technical)

Depends

Say I have a base H₃X and you get H₂X. It is still possible for the K_a < K_b even though it is unlikely.

600

Can I use the 5% rule? K_a = 3.1 x 10^-8

    [x]⁵

-----------

[20x] [5-x]

Yes, on the [5-x]

800

Soda acid or base?

Acid (just common knowledge)

1000

If you put the buffer H₂F with a pH range of 6.1-8.1 in a HCl solution pH 10, will it make it more acidic, basic, it depends, or neither. H₂F has a k_a = π (<-pi)

(Don't guess, you've only got a 25% chance)

Draw out the ICE table

     H₂F  <>  HF^-  +  H⁺

I    ...           0         ...

C   -x           +x        +x

E   ...-x         x        ...+x

So, regardless of pH, or range, or K_a, your pH will have to increase because there is no HF^- in the solution.

Periodic series♣

200

Binary acids strengths increase in which direction?

Up and to the right

    / |

   /

/

400

Does going down the column for central atom for oxyacids increase or decrease strength?

Decrease because electronegativity goes down.

600

Which way does the strength of oxyacid central atoms increase strength?

Up-right

    /\

   /

/

800

J, L, and M are in the same column

arrange the following by strength

H₂LO₃, H₂MO₃, H₂JO₃

H₂JO₃ > H₂LO₃ > H₂MO₃

1000

Which way would conjugate oxyacid base strength increase?

Down left (reverse of acid strength)

      /

   /

|/

Acid types♠

200

What are the three acid types?

Oxyacids, organic acids, binary acids

400

There is a column of elements, 

| A |

| B |

| C |

Which kind of acid will have C as part of the strongest acid?

Binary acids due to atomic radius

600

What are the products of the hydrolysis of Sn(H₂O)₆²⁺?

Sn(H₂O)₅OH^- + H₃O⁺

800

If I put Iron in water, does it increase or decrease pH?

Decrease (complex ions)

1000

If I put Iron in water, does it increase or decrease pH?

Decrease (complex ions)