# Chemistry Kb question need to clarify something

posted by .

the pKb for methylamine is 3.36, what is the Kb for methylamine?

pKa+pKb= 14.00

Kb= 10^-pKb = 4.4x10^-4 is the answer

but HOW?? what is punched into the calculator to get 4.4 x 10^-4??

• Chemistry Kb question need to clarify something -

pKb = 3.36
pKb = -log Kb
3.36 = -logKb
-3.36 = log Kb
Punch in 3.36 and hit the change sign button OR punch in -3.36 directly, then hit the 10^x key. That will return 4.36515E-4 which rounds to 4.36E-4.

• Chemistry Kb question need to clarify something -

-3.36(log button or 10^x button)= syntax error ??

• Chemistry Kb question need to clarify something -

the key sequence will depend on the type of calculator that you have. If it is a VPAM or similar (like a Casio FX-83) then the sequence is something like

<shift><10^><-><3><.><3><6><=>

and the display will show

0.0004365

(depending on how the display is set up).

The exact key sequence will depend on the model of calculator you have.

## Similar Questions

1. ### chemistry

The basicity constant of pyridine can be expressed as pKb = 8.75 what will be the pH of a 1M (1 mole per liter) solution of pyridine in water?
2. ### chemistry

use resonance theory to account for the fact that aniline(pKb 9.37) is a weaker base than cyclohexanamine(pKb 3.34)
3. ### biochemistry

A weak base has pKb = 9.25.. A. Calculate the % ionization at pH = 8.25 B. Calculate the % ionization at pH = 10.25 C. What is the pH when 50% of the weak base is ionized?
4. ### Chemistry

a. what is the pKb of NO2- b. what is the pKa of the hydrazinium ion?
5. ### Chemistry

How many moles of HCl must be added to 100mL of a 0.100 M solution of methylamine (pKb=3.36) to give a buffer having a pH of 10.0?
6. ### Chemistry

Find the pH of a buffer that consists of 0.82 M methylamin (CH3NH2) and 0.71 M CH3NH3Cl (pKb of methylamine (CH3NH2) = 3.35.) I keep getting 3.41, but it says that it's wrong...
7. ### Chemistry

i. Which of the following solutions has the lowest pH (more acidic). Explain you answers. a. a 0.1 M solution of an acid with Ka=2×10-3 or one with Ka=8×10-6 b. a 0.1 M solutions of a base with pKb=4.5 or one with pKb=6.5
8. ### Chemistry

A) Determine the pH of a 0.98 x 10^-2 mol L solution of hydrocyanic acid (HCN) Ka = 4.0 x 10^-10 B) What is the pH of a 0.243mol L solution of methylamine?
9. ### Science

Determine the pkb of methylamine if the kb is 4.4*10^-4.
10. ### chemistry

The pKb of ammonia, NH3, is 4.74 at 25°C.  Which of the following is the Ka of the ammonium ion, NH4+?

More Similar Questions