Chemistry - April 2007

Do I use distilled water or deionized water ?

2007-04-02 20:53:07 · 2 answers · asked by sara 1

BF3 is an electron deficient molecule. B has only 5 electrons. BF3 has a tendency to react with NH3 to form a BF3NH3.

Suggest reason(s) for the reaction and describe the bonding of BF3NH3

2007-04-02 20:46:42 · 1 answers · asked by Anonymous

both carbon dioxide and silicon dioxide are convalent compounds. Why do they have such different melting points?

2007-04-02 20:09:15 · 1 answers · asked by Anonymous

The gauge reads the difference between the tire pressure and the atmospheric pressure (14.7 psi). In other words, the tire pressure is the gauge reading plus 14.7 psi. If the same tire were used in the summer at 110 degrees F and no air had leaked from the tire, what would be the gauge reading in the summer (Hint: degrees C = 5/9(degrees F – 32))

2007-04-02 18:08:29 · 3 answers · asked by bballchic601 1

1. zinc+ nitric acid -- zinc nitrate + nitrogen dioxide + water
2. ammonium sulphate+ potassium hydroxide --- potassium sulphate + ammonia + water

2007-04-02 18:08:20 · 2 answers · asked by Stormy Knight 1

what would be the partial pressure of the oxygen

2007-04-02 18:04:24 · 1 answers · asked by bballchic601 1

Q: Find the pH during the titration of 20 mL of 0.1000 M triethylamine, (CH3CH2)3N (Kb = 5.2 x 10^-4), with 0.1000 M HCl solution after the following additions of titrant: (a) 0 mL; (b) 15 mL; (c) 20 mL; (d) 25 mL.

My Idea: I know that you need to find the excess moles for each addition of titrant. However, I do not know the equation of when the Base (CH3CH2)3N is added to the Acid (HCl). If I can get that, then I can obtain the moles of excess and figure out the concentrations for the Base and Conjugate Acid in order to get pH...

I don't mind if anyone wants to work this problem out and report to me your findings. I just need to find an equation to work with...Thanks for your time! I will award you for your time - the least i can do...

2007-04-02 17:32:55 · 1 answers · asked by Anonymous

Could anyone help me understand this problem, it would be most appreciated! Thanks!

What is the mass of 187L of CO2 gas? The volume is measured at STP.

I think I should start by determining the number of moles present but I'm still confused. Help!

2007-04-02 17:30:23 · 1 answers · asked by ~SMCM101~NYC 2

1. A 54.0 mL sample of oxygen is collected over water at 23C at 770.0 torr pressure. What is the volume of the dry gas at STP? (Vapor pressure of water at 23C=21.1 torr)

2. THe partial pressure of F2 in a mixutre of gases where the total pressure is 1.00 atm is 300. torr. What is the mole fraction of F2?

2007-04-02 17:28:13 · 1 answers · asked by Azumi 2

Im struggling on this one.....

Ammonium hydrogen sulfide is a crystalline solid that decomposes as follows...
NH4HS (s) > NH3 (g) + H2S (g)

Some solid NH4HS is placed in an evactuated vessel at 25 degrees C. After ebilibrium is attained, the total pressure inside the vessel is found to be .659 atm. Some solid NH4HS remains in the vessel at equalibrium. For this decomposition, wirte the expression for Kp and calculate its numerical value at 25 degrees C.

2007-04-02 17:01:57 · 2 answers · asked by Matt B 2

a pic of it would be nice?

2007-04-02 17:00:47 · 9 answers · asked by shchi 2

my idea is that b/c acid-base indicator is a buffer in which its main purpose is to regulate pH. Is that correct???

2007-04-02 16:59:17 · 2 answers · asked by Anonymous

2007-04-02 16:55:10 · 4 answers · asked by redalert 2

Help please, I was gone to my country for 2 weeks and I wasn't even at school for these stuff, and teacher told me to hand in the answers tommorrow,,,,,

9) The following products had their pH tested, drain cleaner (PH 14), stomach acid (pH 2), shampoo (Ph 6), and tomato juice(pH 4.5).
Fill int he following table
Table 1: indicator colour of common solutions

i couldn't make a table when i am asking a question
drain cleaner / stomach acid / shampoo / tomato juice

colour of litmus paper/
colour of phenolphthalein/

i couldn't make a table when i am asking a question

2007-04-02 16:41:19 · 5 answers · asked by ÁØ¸ð ¹ 1

wat is molar enthalpy???

2007-04-02 16:32:52 · 1 answers · asked by Anonymous

Al3+(aq) + 3e- ===> Al(s) E° = -1.66 V
I2(s) + 2e- ===> 2 I-(aq) E° = +0.54 V
Based on these data, under standard conditions,
(a) Al3+(aq) is a stronger oxidizing agent than I2(s) and I-(aq) is a strong reducing agent than is Al(s).

(b) I2(s) is a stronger oxidizing agent than Al3+(aq) and Al(s) is a stronger reducing agent than I-(aq).

(c) Al(s) is a stronger oxidizing agent than I-(aq) and Al3+(aq) is a stronger reducing agent than I2(s).

(d) I-(aq) is a stronger oxidizing agent than Al(s) and I2(s) is a stronger reducing agent than Al3+(aq).

2007-04-02 16:23:34 · 2 answers · asked by gmaghrebi 1

an ore contains Fe sub3 O sub4 and no other iron. the iron in a 53.5 gram sample of the ore is all converted by a series of chemical reactions to Fe sub2 O sub3. the mass of Fe sub2 O sub3 is measured to be 30 grams. what was the mass of Fe sub3 O sub4 in the sample of ore? answer in units of grams.

2007-04-02 16:09:24 · 1 answers · asked by michael v 1

2007-04-02 15:19:55 · 6 answers · asked by Anonymous

2007-04-02 15:17:57 · 1 answers · asked by jolee 1

What is the largest mass of solid NaCl that can be dissolved in 1.000L of 5.00e-3M AgNO3 without a precipitate of AgCl forming? Ksp for AgCl is 1.8e-10

a)0.78 mg
b)86 ug
c)13 ug
d)2.1 ug
e)36 ng

Is it e?

2007-04-02 15:14:28 · 1 answers · asked by bigmanonthewall 3

2007-04-02 14:59:04 · 9 answers · asked by ÐÂ Õ 1

2007-04-02 14:56:06 · 1 answers · asked by Anonymous

why doesnt iodine conduct electricity?...y does graphite conduct electricity? y does calcium chloride conduct electricity?....whats the difference in these substances that cause them to conduct electricity?

2007-04-02 14:50:06 · 1 answers · asked by Anonymous

I know that when you are writing the combustion equation for a compound such as glucose (C6H12O6), the other reactant is O2 and the products are CO2 and H2O.
I was wondering how you would write the complete combustion equation for a non-carbon, hydrogen, and oxygen compound such as barium sulfate(BaSO4).
Reactants and products must balance eachother on both sides of the equation, so would this mean that some BaSO4 would come out on the product side?

2007-04-02 14:41:02 · 2 answers · asked by Anonymous

the 50 ml of hcl acid contained 0.05mol Hcl. show by calculation why the ballon with .6g Mg inflated to about twice the size of the balloon with 0.3g Mg.

my balanced equation: Mg+2HCl -> H2
[yeah they asked to write one] this is a lab question.

2007-04-02 14:29:08 · 2 answers · asked by Stephanie 3

Please help me with my homework.. We were asked to predict a hypothesis for our experiment. This experiment is regarding the surface tension of number. We're gonna place paper clips in water and predict the number of paper clips that can be placed on water before water spills from the container. I guessed about 10 paper clips. Can someone tell me an estimation and a more detailed explanation of what really happened?

2007-04-02 14:18:20 · 3 answers · asked by sallinom_dlanor 1

for instance my schoo did a lab, which we heated in a crucible with cover and potassium chlorate and we had to find the masss of the cricible and cover which was 18.1g, and the mass of crucible,cover, and contents before heateing-19.94g and Mass of crucible cover and contentes AFter heating -19.8g

2007-04-02 13:57:17 · 1 answers · asked by MELLY g 1

Hello,

I am having trouble with my AP Chemistry homework. Here's the problem:

A 0.25 M solution of diethylamine, (CH3CH2)2NH, has a pH of 12.15. What is the Kb of diethylamine?

I figured out the concentration of H+ ions (from the pH) to be 7.08 x 10^-13. I now don't know how to proceed. Can you help me please?

2007-04-02 13:27:51 · 1 answers · asked by eyanyo13 3

What are at least 5 properties of air?

2007-04-02 12:40:29 · 4 answers · asked by yupp. 1

Phenolphthalein indicator is used for vinegar titration and bromthymol blue for strong acid- strong base titration. If we titrate ammonia with hydrochloric acid (weak base- strong acid) where should the equivalence be? What indicator would you use for this titration? Explain how the expected end point affects the transition point of the indicator we should use.

2007-04-02 12:10:20 · 1 answers · asked by Roger 1