Chemistry - December 2007

Im having trouble trying to attempt this conversion problem:
Given: 1km=.62 mile
speed of light=3.0x10^8 m/s
Convert: 89 x 10^6 miles to minutes to the correct amount of significant digits

2007-12-01 07:30:27 · 2 answers · asked by s a 1

Calculate the pH of each of the following solutions.

(a) 0.200 M propanoic acid (HC3H5O2, Ka = 1.3 10-5)
7.29 (i was correct)
(b) 0.200 M sodium propanoate (NaC3H5O2)
13.3 (i was incorrect)
(c) pure H2O
7.00 (obviously correct)
(d) 0.200 M HC3H5O2 and 0.200 M NaC3H5O2
havent tried it yet.
i dont know how to do be without ka

2007-12-01 07:11:42 · 4 answers · asked by poo 2

1. Calcium Chloride
2. Vitamin C
3. Salicylic Acid
4. Magnesium
5. Magnesium Sulfate
6. Sodium Chloride
7. Sucrose

2007-12-01 06:56:20 · 1 answers · asked by Dhoopy 3

Select the reasons why the molecule BF3 is trigonal planar and a molecule with a similar formula, ClF3, is T-shaped.

1. ClF3 has three bonding pairs and two lone pairs.
2. The electron-group geometry for ClF3 is trigonal bipyramidal.
3. BF3 has two bonding pairs and one lone pair.
4. BF3 has two electron groups.
5. BF3 has all bonding pairs

I know number one is right but I am not sure what else is. Help?

2007-12-01 06:46:54 · 3 answers · asked by Donna L 3

What is the coefficient of K2Cr2O7 in the balanced equation?

2007-12-01 06:44:09 · 6 answers · asked by Jesse W 1

Consider the reaction below.

2 POCl3(g) ---->2 PCl3(g) + O2(g)

(a) Calculate G° for this reaction. The Gf° values for POCl3(g) and PCl3(g) are -502 kJ/mol and -270. kJ/mol, respectively.
(b) Is this reaction spontaneous under standard conditions at 298 K?
(c) The value of S° for this reaction is 179 J/K. At what temperatures is this reaction spontaneous at standard conditions? Assume that H° and S° do not depend on temperature.

Okay, so i already got A and B--

a is 464
and b is no

however, i don't understand why b is no.

and c, i don't understand because how can you solve without the enthalpy value??

can someone please help me with B and C?

2007-12-01 06:43:23 · 1 answers · asked by Megan 1

A.) P= 875 torr V=275 mL N=0.0105 mol T= ?
B.) P=? V=0.100 L N=0.200 mol T= 38 degrees C
C.) P=2.50 atm V=? N=3.00 mol T=557.33 degrees F
D.) P=688 mmHg V=986 mL N=? T=565 K

2007-12-01 06:25:14 · 3 answers · asked by confused44 1

2007-12-01 06:23:31 · 3 answers · asked by frog girl 1

Calculate the maximum wavelength of light capable of removing an electron for a hydrogen atom from the energy state characterized by n=1 and by n=2.

2007-12-01 06:14:41 · 3 answers · asked by Anonymous

(Eg-CH3Cl has polar and nonpolar bonds)

2007-12-01 06:12:20 · 1 answers · asked by don 2

Let's say I have H2+I2----->2HI
volume is 1L
atm's are .5H, 1atm I and 5.2atm's HI
temp is 0 celcius

I have the equlibrium constant formule (products over reactants), but how do i get the values to plug in?

2007-12-01 06:10:46 · 1 answers · asked by mikala m 2

Calculate the de Broglie wavelength for each of the following.
a.) an electron with a velocity 10.% of the speed of light
b.) a tennis ball (55g) served at 35 m/s (~80 mi/h)

2007-12-01 06:09:59 · 1 answers · asked by Anonymous

Pressures can be expressed in traditional units (torr/atm; 1 atm= 760 torr), or in SI units (Pa; bar = 100 Pa used instead of atm). Which do you think is better, and why?

2007-12-01 05:50:03 · 5 answers · asked by Facts Matter 7

Problems involving gases can be solved using

PV = nRT

or by using 22.4L as the volume of 1 mol at STP, and

P1V1/T1 = P2V2/T2

Which do you think is better (of course, they come down to the same thing in the end), and why?

2007-12-01 05:44:40 · 5 answers · asked by Facts Matter 7

Hey,

I am studying for this chemistry exam, and am quite confused with this acidic concept. In particular, the prompt asks:

In which of the following pairs is the first compound more acidic?

a. HCl HBr

b. HClO2 HBrO2

c. HNO3 H2SO3

d. A and B

e. B and C

The correct answer is E. I understand that HNO3 is a strong acid, but what maces choice B stronger then choice A? I know that HBr is stronger because it is a bigger element, but Isnt answer B the exact same?

Or am I missing something?

Thanks in advance

2007-12-01 05:18:16 · 3 answers · asked by Justin A 1

On a small scale, calcium can be isolated through the retion of calcium chloride with sodium metal
CaCl2 + 2Na --> Ca + 2NaCl
Question:
How many moles of Na are needed to react with 7.00 mol CaCl2?

Please help and could you please explain how to do it aswell

2007-12-01 05:04:04 · 3 answers · asked by Anonymous

the gold has other metals and minerals some raw out of streams and dry creekbeds

2007-12-01 04:46:21 · 5 answers · asked by Anonymous

2007-12-01 04:44:57 · 2 answers · asked by Anonymous

Write a balanced chemical equation which corresponds to the following equilibrium constant expression.

K =[F-] [H3O+] / [HF]

a.HF(aq) f F-(aq) + H3O+(aq)
b.H+(aq) + OH-(aq) f H2O(λ)
c.HF(aq) + H2O(λ) f F-(aq) + H3O+(aq)
d.F-(aq) + H3O+(aq) f HF(aq) + H2O(λ)
e.F-(aq) + H3O+(aq) f HF(aq)

2007-12-01 04:25:08 · 2 answers · asked by Anonymous

what happens when the popcorn is heated?
what causes the popcorn to "pop"?

thanks <3

2007-12-01 03:31:40 · 5 answers · asked by crazy&lazy 5

2007-12-01 02:59:14 · 2 answers · asked by nymetsrule7591 1

2007-12-01 00:44:49 · 2 answers · asked by Anonymous

For example if i have 2 C2H6 + 7 O2 = 4 CO2 + 6 H2O, and i have 100g of C2H6 and 100g of 02, when finding the number of moles of each, do i have to times the Mass divided by Molar Mass by the coefficient? Or do i times the molar mass by the coefficient before dividing? Or do i not have to times at all? What im trying to say is HOW DO I FIND THE NUMBER OF MOLES?? Please read this question carefully (im confused enough as it is) and answer asap!!

Cheers all!

2007-12-01 00:39:16 · 5 answers · asked by Anonymous

2007-12-01 00:36:26 · 2 answers · asked by Anonymous

2007-12-01 00:33:42 · 4 answers · asked by Anonymous