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Stels [109]
3 years ago
6

A sample of an unknown gas takes 371 s to diffuse through a porous plug at a given temperature.

Chemistry
1 answer:
blsea [12.9K]3 years ago
5 0

Answer:

125.84 g/mol is the molar mass of the unknown gas.

Explanation:

Let the volume of the gases effusing out be V.

Effusion rate of the unknown gas = R=\frac{V}{371 s}

Effusion rate of the nitrogen gas = r=\frac{V}{175 s}

Molar mass of unknown gas = m

Mass of nitrogen gas = 28 g/mol

Graham's law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}

\frac{R}{r}=\sqrt{\frac{28 g/mol}{M}}

\frac{\frac{V}{371 s}}{\frac{V}{175s}}=\sqrt{\frac{28 g/mol}{M}}

\frac{175 s}{371 s}=\sqrt{\frac{28 g/mol}{M}}

M=\frac{28 g/mol\times 371\times 371}{175\times 175}=125.84 g/mol

125.84 g/mol is the molar mass of the unknown gas.

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Minchanka [31]

Answer:

molecular formula of liquid = C₈H₁₈

Explanation:

First we determine the empirical formula of the liquid:

Number of moles of each element present in the liquid = % mass / molar mass

For Carbon, (molar mass = 12.01 g/mol) : 84.2/12.01 =7.011 moles

For Hydrogen (molar mass = 1.01 g/mol) : 15.8/1.01 = 15.643

Simplest mole ratio of the elements, C : H  is given by:

C = 7.011/7.011 = 1.0

H = 15.643/7.011 = 2.23

Multiplying through with 5, C:H = 5:11

Therefore, empirical formula is C₅H₁₁

The molecular mass of the liquid is next determined:

Using PV = nRT to find the number of moles of the liquid present

P = 5.0 atm; V = 568.0 mL = 0.568 L; R = 0.082 L*atmmol⁻¹ K⁻¹; T = 273 + 120 = 393 K

n = PV/RT = (5*0.568)/0.082*393

n = 0.088 moles

Molar mass of liquid = mass/no of moles = 10.0 g/ 0.088 moles = 113.63 gmol⁻¹

Molecular formula = n(empirical formula)

Molar mass of empirical formula, C₅H₁₁ = 71 gmol⁻¹

n = molecular mass/empirical mass = 113.63/71 = 1.6

Therefore, molecular formula =  1.6*(C₅H₁₁) = C₈H₁₈

6 0
3 years ago
Please help with 3 and 4
mafiozo [28]
3. volume of gas because its changing because of the temperature
4. 67.6 breaths per minute
     65+73+67+71+62=338/5=67.6
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7 0
3 years ago
At a certain temperature the vapor pressure of pure chloroform (CHCl3) is measured to be 91. torr. Suppose a solution is prepare
OleMash [197]

Answer:

P_{CCl_4}=52.43torr

Explanation:

Hello there!

In this case, sine the solution of this problem require the application of the Raoult's law, assuming heptane is a nonvolatile solute, so we can write:

P_{CCl_4}=x_{CCl_4}P_{CCl_4}^{vap}

Thus, we first calculate the mole fraction of chloroform, by using the given masses and molar masses as shown below:

x_{CCl_4}=\frac{140/153.81}{140/153.81+67.1/100.21}=0.576

Therefore, the partial pressure of chloroform turns out to be:

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Regards!

3 0
3 years ago
Which sentence is a scientific statement?
LekaFEV [45]

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Statement C is not a scientific statement as there is no science behind watching baseball or ice hockey, it depends on the liking of today's people.

Statement D is a scientific statement because this can be scientifically proved.  

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3 years ago
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1. electrostatic interactions 
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<span>4. hydrogen bonding </span>
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