chemistry help?
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
Original post by strawberry lover
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
At r.t.p, you may be aware that 1.00 mol of any gas occupies 24 dm^3.
You should also know that number of particles = 6.02 x 10^23 x moles
What does this imply about the number of particles of gas in options C and D?
Original post by strawberry lover
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
A) 1g of hydrogen molecules
B) 1g of helium molecules
C) 1dm3 of hydrogen molecules
D) 1dm3 of helium molecules
The answer is A, can someone please explain why and how they got to this answer?
you can calculate by converting first two options into dm3 as well..convert all of them into moles..then you will get to the answer...
Original post by RaviS
How can the answer would be a
can someone explain this question please
Original post by jefftim123567
can someone explain this question please
1) Focus on the number of moles (mol) of each sample.
2) Calculate the number of moles (mol) of each sample.
3) If you compare the number of moles in each of the samples, you can find the correct answer (A).
PS: When you post your work, I'll provide small hints to help you continue on your own. If you're still struggling after receiving the hints above, you may need more guidance. In that case, I'll ask you to clarify what's unclear and provide additional explanations to help you understand the solution.
Bye,
Sandro
(edited 4 months ago)
Original post by jefftim123567
can someone explain this question please
At room temperature, the volume occupied by 1 mole of any gas is about 24 dm^3. That would imply that options C and D involve the same number of moles of gas (0.0416… mol) and so this eliminates both as there can only be one right answer.
Now calculating moles using moles = (mass in g)/(molar mass in g/mol):
A: H2 has a molar mass of 2 g/mol, so 1 g = 0.5 mol
B: He has a molar mass of 4 g/mol, so 1 g = 0.25 mol
Since option A has the largest number of moles, it must be the right answer.
(edited 4 months ago)
Quote
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
Unquote
Since the problem requires the greatest number of the particles listed, I think the problem can be posed and then solved as follows.
You have to calculate the number of moles in each sample and then transform them into number of molecules.
A) 1g of hydrogen molecules (H2)
Molar mass of H2: 2 g/mol
Number of moles: (1 g)/(2 g/mol) = 0.5 mol
Number of molecules: 0.5 mol x 6.022 x 10^23 molecules/mol = 3.011 x 10^23 molecules
B) 1g of helium molecules (He)
Molar mass of He: 4 g/mol
Number of moles: (1 g)/(4 g/mol) = 0.25 mol
Number of molecules: 0.25 mol x 6.022 x 10^23 molecules/mol ≈ 1.506 x 10^23 molecules
C) 1dm^3 of hydrogen molecules (H2) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
D) 1dm^3 of helium molecules (He) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
You can see that 1 g of hydrogen molecules (A) contains the greatest number of molecules (3.011 x 10^23). So, the answer is A.
Regards,
Sandro
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
Unquote
Since the problem requires the greatest number of the particles listed, I think the problem can be posed and then solved as follows.
You have to calculate the number of moles in each sample and then transform them into number of molecules.
A) 1g of hydrogen molecules (H2)
Molar mass of H2: 2 g/mol
Number of moles: (1 g)/(2 g/mol) = 0.5 mol
Number of molecules: 0.5 mol x 6.022 x 10^23 molecules/mol = 3.011 x 10^23 molecules
B) 1g of helium molecules (He)
Molar mass of He: 4 g/mol
Number of moles: (1 g)/(4 g/mol) = 0.25 mol
Number of molecules: 0.25 mol x 6.022 x 10^23 molecules/mol ≈ 1.506 x 10^23 molecules
C) 1dm^3 of hydrogen molecules (H2) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
D) 1dm^3 of helium molecules (He) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
You can see that 1 g of hydrogen molecules (A) contains the greatest number of molecules (3.011 x 10^23). So, the answer is A.
Regards,
Sandro
(edited 4 months ago)
Original post by Nitrotoluene
Quote
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
Unquote
Since the problem requires the greatest number of the particles listed, I think the problem can be posed and then solved as follows.
You have to calculate the number of moles in each sample and then transform them into number of molecules.
A) 1g of hydrogen molecules (H2)
Molar mass of H2: 2 g/mol
Number of moles: (1 g)/(2 g/mol) = 0.5 mol
Number of molecules: 0.5 mol x 6.022 x 10^23 molecules/mol = 3.011 x 10^23 molecules
B) 1g of helium molecules (He)
Molar mass of He: 4 g/mol
Number of moles: (1 g)/(4 g/mol) = 0.25 mol
Number of molecules: 0.25 mol x 6.022 x 10^23 molecules/mol ≈ 1.506 x 10^23 molecules
C) 1dm^3 of hydrogen molecules (H2) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
D) 1dm^3 of helium molecules (He) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
You can see that 1 g of hydrogen molecules (A) contains the greatest number of molecules (3.011 x 10^23). So, the answer is A.
Regards,
Sandro
Which sample, measured at room temperature and pressure, contains the greatest number of the stated particles?
Unquote
Since the problem requires the greatest number of the particles listed, I think the problem can be posed and then solved as follows.
You have to calculate the number of moles in each sample and then transform them into number of molecules.
A) 1g of hydrogen molecules (H2)
Molar mass of H2: 2 g/mol
Number of moles: (1 g)/(2 g/mol) = 0.5 mol
Number of molecules: 0.5 mol x 6.022 x 10^23 molecules/mol = 3.011 x 10^23 molecules
B) 1g of helium molecules (He)
Molar mass of He: 4 g/mol
Number of moles: (1 g)/(4 g/mol) = 0.25 mol
Number of molecules: 0.25 mol x 6.022 x 10^23 molecules/mol ≈ 1.506 x 10^23 molecules
C) 1dm^3 of hydrogen molecules (H2) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
D) 1dm^3 of helium molecules (He) at RTP
Number of moles: (1 dm^3)/(24 dm^3/mol) = 0.0417 mol
Number of molecules: 0.0417 mol x 6.022 x 10^23 molecules/mol = 2.51 x 10^22 molecules
You can see that 1 g of hydrogen molecules (A) contains the greatest number of molecules (3.011 x 10^23). So, the answer is A.
Regards,
Sandro
You can calculate the numbers of molecules, but honestly that’s just an extra step and calculating moles is usually enough working to be sure.
In this particular question, you could even stop upon determining the molar masses of H2 and He - all the numbers of moles will be found by evaluating 1/x (where x is either a molar mass or 24 dm^3 mol^-1, whichever is appropriate) and once you see that the molar mass of H2 is the smallest thing 1 could be divided by, it’s obvious that 1 g of H2 has the most number of moles and so the most number of particles.
Remember this is a multiple choice question, not something that actually requires you to give a numerical answer to get the marks.
(edited 4 months ago)
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