General Knowledge - Chemistry - Discussion

Discussion Forum : Chemistry - Section 1 (Q.No. 7)
7.
The molecules of which gas have highest speed?
H2 at -73oC
CH4 at 300 K
N2 at 1,027oC
O2 at 0oC
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
83 comments Page 1 of 9.

MARCIALBORLA said:   6 months ago
Let's solve it step- by- step:

Formula for molecular speed ( root mean square speed, urms):

Urms=√3RT/M

R=universal gas constant.
T= temperature in Kelvin.
M= molar mass (in kg/mol).

Higher t/m-higher speed. So we need to compare T/M for each gas.

Given:

A. H2 at -73⁰C _T= -73+273=200 k,M(H2)=2 g/mol = 0.002 kg/mol.
B. CH4 at 300 K_M(CH4) = 16 g/mol = 0.016 kg/mol,
C. N2 at 1,027⁰C_T=1,027 + 273 = 1300 k, M(N2) = 28 g/mol = 0.028 kg/mol,
D. O2 at 0⁰C_T=0 + 273 = 273K, M(02) = 32 g/mol = 0.032 kg /mol.

Now calculate T/M roughly:

A: 200/0.002 = 100,000.
B: 300/0.016 = 1 8,750.
C.1300/0.028 = 46,429.
D.273/0.032 = 8,531.

Result

Highest value is 100,000 for A(H2 at -73⁰C).

Thus, the Answer: A. H2 at -73⁰C.
(1)

Liah said:   1 year ago
Please explain it more clearly.
(1)

Pama said:   3 years ago
Hydrogen gas with higher temperature and lower molecular weight have higher molecular speed.

Among the given gases, hydrogen at 50°C has a maximum value of T/M and the highest speed. The correct option is A.
(1)

Daniel Olabode said:   3 years ago
Option A is correct using temp/molar mass.

H2:73/2 = 36.5,
CH4:300/16 = 18.45,
N2:1027/28 = 36.67,
O2:0/32 = 0.

H2 and N2 if we compare their masses hydrogen is the lightest.

I hope you will understand.
(5)

M. Shoaib said:   5 years ago
I think C is correct answer.

Anu said:   6 years ago
Please explain the right answer clearly.
(1)

Prince said:   6 years ago
Step 1: Convert 'c to kelvin
Step 2:use formula speed= √(RT/M).

Keeping R constant in each case. By calculating, option 1 is correct.
(2)

Naveed sultan said:   6 years ago
A is right because of low mass of hydrogen gas.

Guddu Bharti said:   7 years ago
Gas molecules speed = temperature/molecular wt.
Hydrogen gas has the highest value of that ratio.
So hydrogen gas has high-speed compared to other gasses.

Pangetmo said:   7 years ago
A is correct because of the speed of molecules increases in hotter temperature.


Post your comments here:

Your comments will be displayed after verification.