Asked Oct 12, 2019

A gas mixture is made by combining 7.5 g each of Ar, Ne, and an unknown diatomic gas. At STP, the mixture occupies a volume of 18.53 L.

What is the molar mass of the unknown gas?

Identify the unknown gas.


Expert Answer

Step 1


Mass of Ar, Ne and an unknown diatomic gas = 7.5 g

Moles of Ar and Ne can be calculated as:


Image Transcriptionclose

7.5 g Mass of Ar Moles of Ar -0.1875 mol Molar mass of Ar 40 g/mol 7.5 g Mass of Ne Moles of Ne = 0.375 mol Molar mass of Ne 20 g/mol

Step 2

Volume, V = 18.53 L

At STP: Pressure, P = 1 atm and temperature, T = 273 K

The total number of moles in the gas mixture can be calculated using the ideal gas equation as:


Image Transcriptionclose

PV nRT PV n RT 1 atm x 18.53 L Latm x 273 K 0.0821 mol K n 0.827 mol

Step 3

The molar mass of the unknown g...


Image Transcriptionclose

Total moles Moles of Ar moles of Ne moles of unknown gas Moles of unknown gas = Total moles - (Moles of Ar Moles of Ne) Moles of unknown gas 0.827 mol (0.1875 mol 0.375 mol) Moles of unknown gas = 0.2645 mol 7.5 g Mass 28.35 g/mol Molar mass of unknown gas - Moles 0.2645 mol


Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in

Ideal gases

Related Chemistry Q&A

Find answers to questions asked by student like you
Show more Q&A

Q: why is the temperature cooled to 100degree celcius in the reaction of benzil and 1,3dipenhyl acetone...

A: The mechanism involved in the reaction between benzil and 1,3-diphenylacetone is given by


Q: Draw the two possible chair conformations of the (+)- B- Galactose molecule shown below, using the a...

A: The given structure of (+)-β-Galactose is shown below.


Q: Be sure to answer all parts. (1) Deduce the formula of iron(III) sulfide.Click in the answer box to ...

A: An ionic compound should be neutral. Hence, the number of negative and positive charges must be same...


Q: Checkin if I did part b) correctly and help with c) and d)

A: The spatial arrangement of atoms in a molecule obtained by rotation around carbon - carbon single bo...


Q: How many moles of sodium (Na) are in 1.75×1024 Na1.75×1024 Na atoms?

A: Number of moles is calculated using formula,


Q: 1.34 (a) What is the highest energy photon that can be absorbed by a ground-state hydrogen atom with...

A: (a)The highest energy of photon that is absorbed by Hydrogen atom can be determined using the given ...


Q: Please answer questions 4a, 4b, and 4c. The questions are provided in the attached image. Thank you.

A: (a) The equation of dehydration of the given hydrated salt is given below.


Q: Mg + Cl2 --> MgCl2  If 5.00g of magnesium is combined with 10.0g of chlorine. Calculate the theor...

A: Determine limiting reagent:


Q: Calculate the volume in milliliters of a 1.25/molL sodium carbonate solution that contains 275.mmolo...

A: The number of moles for a given chemical species refers to the ratio of mass to the molar mass. The ...