Chemistry - April 2007

1. B is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for
HB+? (a) HB+ + H2O <==> B + H¬3O+
(b) HB+ + H3O+ <==> H2B2+ + H2O
(c) B + H2O <==> HB+ + OH-
(d) HB+ + OH- <==> B + H2O
(e) B + H3O+ <==> HB+ + H2O



2. What is the pH of a 0.015 M aqueous solution of barium hydroxide?
(a) 12.48 (b) 12.18 (c) 1.82 (d) 10.35 (e) 1.52


3. The solubility of lead (II) chloride (PbCl2) is 1.6 x 106-2 M. What is the Ksp of PbCl2?

4. The Ka of hypochlorous acid is 3.0 x 106-8 at 25. What is the % ionization of hypochlorous acid in a .015-M aqueous solution of HClO at 25?

5 .15-M aqueous solution of the weak acid HA at 25 degrees celcius has a pH of 5.35. What is the Ka value for HA?














If you could please explain your answer(s), that would be perfect!!
thanks!

2007-04-28 15:37:37 · 2 answers · asked by bree 3

The speed of a chemical reaction roughly doubles for every 10 degrees Celsius temperature rise. When you pull the pin on a hand grenade acid is released, eats away a metal wire and a few seconds later the wire breaks and a detonator goes off. So on a hot day in Iraq it should detonate sooner than on a cold day in Chechnya. How do you know when it will explode?

2007-04-28 14:53:44 · 5 answers · asked by zee_prime 6

what are the physical and chemical properties of salts?

2007-04-28 14:09:06 · 2 answers · asked by loally 2

What is a mathematical statement of the elationship between pressure and volume?

2007-04-28 14:03:34 · 3 answers · asked by hahahahahaha 1

Iron has a density of 7.86 g cm-3. How many pounds does a block of iron with a volume
of 1.65 cubic feet weigh? 1pound = 0.4536 kg, 1 foot = 12 in., 1 in. = 2.54 cm.

2007-04-28 13:57:00 · 4 answers · asked by dimo_e7 2

2007-04-28 13:54:55 · 4 answers · asked by Anonymous

2007-04-28 13:52:11 · 2 answers · asked by Whatever 1

2007-04-28 13:51:24 · 3 answers · asked by Whatever 1

2007-04-28 13:50:22 · 6 answers · asked by Whatever 1

WHat are the products of the following reactions? Also please specify whether it's E1 or E2?

A) (CH3CH2)3CBr in NaNH2, NH3 solvents

B) CH3CH2CH2CH2Cl in KOC(CH3)3, (CH3)3COH solvents

2007-04-28 12:52:14 · 3 answers · asked by flyboy87 1

how do u make one i know u use baking soda and vinegar but how much

2007-04-28 12:10:52 · 1 answers · asked by th3_ch0s3n_0n3 2

What is the concentration of the original KOH solution if 84.0 mL of the KOH solution reacts with 3.40 g of H3PO4?

2007-04-28 12:10:50 · 2 answers · asked by wonderer 1

IS there something that makes it more pure than the distilled water? How? Thanks!

2007-04-28 10:11:22 · 4 answers · asked by sakurika1128 2

How many grams of hydrochloric acid are reacted when 1.20 mol of zinc is reacted with 7.80 mol of hydrochloric acid, as shown above?

i tried a bunch of things..but doesn't seem to be correct. Need help!!

2007-04-28 09:59:16 · 3 answers · asked by wonderer 1

H2O2 + KNaC4H4O6 + CoCl2 -------> ? would there be an intermediate?

2007-04-28 09:42:49 · 2 answers · asked by mrs. 김재중 2

This is probably a dumb question. H2 will not explode without oxygen, so it's only dangerous when it's outside of a tank. But if H2 and O2 are pressurized together, they're obviously flammable. But will compressing them alone be enough to cause an explosion inside a low pressure tank? Thank you for bearing with me :)

2007-04-28 09:35:15 · 2 answers · asked by DontBlowMeUp! 1

2007-04-28 09:15:16 · 4 answers · asked by (notso)Gloriouspipecleaner 3

2007-04-28 09:08:58 · 1 answers · asked by Nabeel 2

2007-04-28 08:45:32 · 2 answers · asked by Foxychick 1

2007-04-28 08:41:29 · 4 answers · asked by sandysdachshund 3

2007-04-28 08:39:12 · 1 answers · asked by mrchrister93023 1

can anyone tell me how I calculate the enthalpy change of formation of ethene given that the enthalpies of combustion of ethane, carbon and hydrogen are -1411, 393 -286 kj/mol respectively

2007-04-28 08:19:29 · 2 answers · asked by Anonymous

in counts per minute per gram, of carbon-14 in the sample?

The decay rate of carbon-14 in wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years.

For a first order reaction the rate R = −k N so the ratio of rates at two different times is given by R(t1)/R(t2) = N(t1)/N(t2).
For nuclear decay the rate is ofen is expressed in units of counts per unit of time.

2007-04-28 08:19:14 · 2 answers · asked by Anonymous

2007-04-28 07:58:35 · 2 answers · asked by dannygwenz 2

balanced equation: Al(OH)3 + 3 HCl -> AlCl3 + 3 H2O

2007-04-28 07:46:01 · 4 answers · asked by soccrrulz21 2

For a first order reaction the rate R = −k N so the ratio of rates at two different times is given by R(t1)/R(t2) = N(t1)/N(t2).
For nuclear decay the rate is ofen is expressed in units of counts per unit of time.


A chemists determines that a sample of petrified wood is 3.50 X 103 years old. What is the rate of decay, in counts per minute per gram, of carbon-14 in the sample? The decay rate of carbon-14 in wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years.

2007-04-28 07:44:44 · 1 answers · asked by guitarx313 1

2007-04-28 07:25:29 · 2 answers · asked by Anonymous

i know the balanced equation is H3PO4 + 3 NaOH -> Na3PO4 + 3 H2O

how do i find the amt. of mL needed to react?

2007-04-28 07:21:11 · 2 answers · asked by soccrrulz21 2

As well as K2Cro4 with Ca(No3)2...

2007-04-28 07:20:53 · 1 answers · asked by Isabee 2

I was working with Q sur= mxCx(T*1-T*2)

but this problem is different, what do i do?
what is the sprcific heat of nickel if the temperature of a 32.2g sample of nickel is increased by 3.5 celsius when 50 joules os heat is added.

Is there a formula?? how can i get to the answer if you could please explain?
the answer is (0.44J/g x celsuis)
but i don't know how to get there...
thanks.

2007-04-28 07:16:14 · 1 answers · asked by Anonymous