|
|
|
|
New Member
|
|
Jul 30, 2009, 11:23 PM
|
|
Figuring out the volume of gas
A sample of gas is warmed from 30.0 oC to 90.0 oC at a constant pressure.
Its initial volume is 1.75 liters. What is the final volume of the gas.
|
|
|
New Member
|
|
Jul 30, 2009, 11:24 PM
|
|
Determining the partial pressure of carbon dioxide
A mixture of oxygen, hydrogen, nitrogen and carbon dioxide
In a two liter flask has a total pressure of 1.251 atm.
The partial pressure of oxygen, hydrogen, and nitrogen
Are 0.210, 0.145, and 0.235 atm, respectively. Use Dalton's
Law of partial pressures to determine the partial pressure
Of the carbon dioxide.
|
|
|
New Member
|
|
Jul 30, 2009, 11:25 PM
|
|
Ammonia as a weak base
Ammonia’s behavior as a weak base is best explained as a
a. a source of hydroxide ions.
b. a proton donor
c. a proton acceptor
d. a nonelectrolyte
e. none of the above.
Would the answer be "c" because base is defined as a proton acceptor?
|
|
|
New Member
|
|
Jul 30, 2009, 11:27 PM
|
|
Hydrogen bonding
Hydrogen bonding in water contributes to
a. a decreased boiling point b. an increased vapor pressure
c. a decreased melting point d. an increase in volume on freezing
e. none of the above.
This was on a homework assignment and I put "e" because I wasn't sure. Probably wrong huh?
|
|
|
New Member
|
|
Jul 30, 2009, 11:27 PM
|
|
The pH of cola
The pH of many cola ‑ type drinks is about 3.0. How many times
Greater is the hydronium ion concentration in these drinks than
In neutral water?
|
|
|
New Member
|
|
Jul 30, 2009, 11:29 PM
|
|
Changing the temperature of hydrogen gas
Changing the temperature of 4.0 mol of hydrogen gas at
Constant pressure from 100 oK to 200 K will
a. increase its mass by a factor of three.
b. decrease the volume that the gas occupies.
c. increase the kinetic energy of the hydrogen molecules.
d. decrease the density by a factor of two.
For this homework question I picked "b" am I correct?
|
|
|
New Member
|
|
Jul 30, 2009, 11:30 PM
|
|
Moles of gas
In one experiment, a dry sample of an unknown
Gas was collected. Its volume at 745 mm Hg and
63.0 oC was 815.5 mL. How many moles of this gas
Was obtained?
|
|
|
New Member
|
|
Jul 30, 2009, 11:38 PM
|
|
pH of a solution
What is the pH of a solution with a hydronium ion
concentration of 2.40 x 10‑4
|
|
|
Ultra Member
|
|
Jul 31, 2009, 06:15 AM
|
|
Originally Posted by dsdegu01
A sample of gas is warmed from 30.0 oC to 90.0 oC at a constant pressure.
Its initial volume is 1.75 liters. What is the final volume of the gas.
i=initial and f=final.
Just use the formula
Since the pressure is constant, we can omit the P's.
Plug your knowns into and solve for
|
|
|
Uber Member
|
|
Jul 31, 2009, 09:51 AM
|
|
Originally Posted by dsdegu01
Changing the temperature of 4.0 mol of hydrogen gas at
constant pressure from 100 oK to 200 K will
a. increase its mass by a factor of three.
b. decrease the volume that the gas occupies.
c. increase the kinetic energy of the hydrogen molecules.
d. decrease the density by a factor of two.
for this homework question i picked "b" am i correct?
Nope. In fact, the volume will increase. You know the formula for ideal gas?
Well, pressure is kept constant, the number of moles is constant, R is a constant. Only V and T are variables. So, V is directly proportional to T. Since you increase T, you'll have an increase in Volume.
Let's see the others.
a. Mass is constant, since the number of moles is constant.
c. True, upon heating (with no change of state) a substance gets more kinetic energy. It is that energy which gives you the temperature.
d. Since you increased temperature by a factor of 2 (from 100 to 200) the volume will also increase by a factor of 2. Density is inversely proportional to volume when mass is constant, so the density will decrease by a factor of 2.
Something seems wrong here... c and d are correct. Are you sure you didn't make a mistake in typing? Or maybe the temperature is not in Kelvin, then d will not be the answer.
|
|
|
Uber Member
|
|
Jul 31, 2009, 09:54 AM
|
|
Originally Posted by dsdegu01
In one experiment, a dry sample of an unknown
gas was collected. Its volume at 745 mm Hg and
63.0 oC was 815.5 mL. How many moles of this gas
was obtained?
Use the formula I just gave you. Be careful though. The formula is valid for the units of Pascal for pressure, metre cube for volume, moles for the number of moles, joules per kelvin per mole for the constant R (which has a value of 8.31) and kelvin for temperature.
|
|
|
Uber Member
|
|
Jul 31, 2009, 09:59 AM
|
|
Originally Posted by dsdegu01
What is the pH of a solution with a hydronium ion
concentration of 2.40 x 10‑4
pH is given by the logarithm of the reciprocal of the molar concentration of the hydrogen ion in the solution:
Since a hydronium ion has a hydrogen ion, you can take the concentration of the hydronium ion as the concentration of the hydrogen ion.
|
|
|
Uber Member
|
|
Jul 31, 2009, 10:53 AM
|
|
Originally Posted by dsdegu01
The pH of many cola ‑ type drinks is about 3.0. How many times
greater is the hydronium ion concentration in these drinks than
in neutral water?
Use the formula for pH I just gave you.
|
|
|
Uber Member
|
|
Jul 31, 2009, 10:59 AM
|
|
Originally Posted by dsdegu01
Ammonia’s behavior as a weak base is best explained as a
a. a source of hydroxide ions.
b. a proton donor
c. a proton acceptor
d. a nonelectrolyte
e. none of the above.
would the answer be "c" because base is defined as a proton acceptor?
No. What determines the strength of a base is its ability to dissociate and form hydroxide ions in water. Therefore, the answer is e. Being a proton acceptor doesn't automatically make it a weak base. As you said, the definition of a base is a substance that accepts a proton. All bases are proton acceptors, but some are strong bases, and others weak bases. So, you cannot have c as answer.
|
|
|
Uber Member
|
|
Jul 31, 2009, 11:53 AM
|
|
Originally Posted by dsdegu01
A mixture of oxygen, hydrogen, nitrogen and carbon dioxide
in a two liter flask has a total pressure of 1.251 atm.
The partial pressure of oxygen, hydrogen, and nitrogen
are 0.210, 0.145, and 0.235 atm, respectively. Use Dalton's
Law of partial pressures to determine the partial pressure
of the carbon dioxide.
The formula for finding the partial pressure is:
Where P is the pressure, n is the number of moles.
For solving the question more easily, look here.
Partial pressures of gases add up to make the total pressure. Can you therefore find the partial pressure carbon dioxide provides?
|
|
|
New Member
|
|
Jul 31, 2009, 09:18 PM
|
|
I am actually taking an online class and my teacher has been MIA for the past 2 weeks and I really need serious help. I'm a music major and am not very good in chemistry and no one that I know can I really help me with this. I tried calling my teacher and emailing him a ton of times. So although it looks as though I'm mooching I really just want help. Isn't that what this website is about?
|
|
|
New Member
|
|
Jul 31, 2009, 09:20 PM
|
|
And also... some of this questions I posted I had already answered and turned in I just didn't feel good about them and wanted to know if I was correct and how to do it the correct way.
|
|
|
New Member
|
|
Jul 31, 2009, 09:31 PM
|
|
Originally Posted by Unknown008
The formula for finding the partial pressure is:
Where P is the pressure, n is the number of moles.
For solving the question more easily, look here.
Partial pressures of gases add up to make the total pressure. Can you therefore find the partial pressure carbon dioxide provides?
so would the partial pressure of carbon dioxide be 0.661 atm?
|
|
|
New Member
|
|
Jul 31, 2009, 10:28 PM
|
|
Originally Posted by Unknown008
pH is given by the logarithm of the reciprocal of the molar concentration of the hydrogen ion in the solution:
Since a hydronium ion has a hydrogen ion, you can take the concentration of the hydronium ion as the concentration of the hydrogen ion.
- log 2.40 x 10^-4 =3.62
would this be correct?
|
|
Question Tools |
Search this Question |
|
|
Check out some similar questions!
Figuring out area
[ 7 Answers ]
I need to figure out an area for landscaping glass. THere are four separate sections 21 feet 7 inches by 6 inches. 26 feet 4 inches by 7 inches. 12 feet by 12 inches and 14 feet 8 inches by 10 inches. If I need 7lbs of product per square foot how much product would I need?
Figuring out fantasy
[ 24 Answers ]
OK this fantasy stuff can some one help me with please, I , as you may have read already have so many problems with sex, and its been sugested that I learn to fantasise. Right now comes my problem, what on earth do I do? So I lay back shut my eyes and think? Of what? Hubby? Doing what? What ever it...
Figuring out how much I owe
[ 9 Answers ]
I moved this past June from Washington, DC to NYC. I am trying to figure out how much more in taxes I might have to pay, besides what is taken out of my paycheck biweekly. I am a single person with no dependents so I have the standard deductions for a single filer. The first half of the year, I...
Figuring out how much I owe... Part II...
[ 1 Answers ]
Hi ATL Tax Expert:
Thanks for your response! My only question to your answer is why my federal tax liability would be 34,100 based on 150K income? I worked half a year making 67K and the other half of the year making 83K. Therefore, wouldn't my federal tax be based on the average of 67K and 83K,...
I need help with figuring this out
[ 3 Answers ]
Hello Everyone,
Sorry, this may be kind of long, but advise me if you can. I am a college student (senior) and I met a guy 3 years ago as a freshman. (Yes, we had sex... safe sex of course). I don't really remember why we stopped talking 3 years ago, but I recently saw him on the street....
View more questions
Search
|