Hydrocarbon molecular weight grade 11

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SUMMARY

The discussion centers on calculating the molecular weight of a gaseous hydrocarbon using the Ideal Gas Law equation, PV=nRT. Given a sample mass of 0.185g, a volume of 110 cm³, a temperature of 26°C, and a pressure of 743 mmHg, participants clarify the process of determining the number of moles (n) by rearranging the equation to n = PV/RT. The conversion of units is emphasized as a critical step before substituting values into the equation to find the molecular weight in g/mol.

PREREQUISITES
  • Understanding of the Ideal Gas Law (PV=nRT)
  • Knowledge of unit conversions (e.g., cm³ to L, Celsius to Kelvin)
  • Familiarity with basic chemistry concepts (moles, molecular weight)
  • Ability to perform calculations involving pressure, volume, and temperature
NEXT STEPS
  • Learn about unit conversions for gas calculations, specifically cm³ to liters.
  • Study the Ideal Gas Law in detail, including its applications and limitations.
  • Explore how to calculate molecular weight from experimental data.
  • Investigate the effects of temperature and pressure on gas behavior.
USEFUL FOR

High school chemistry students, educators teaching gas laws, and anyone needing to understand molecular weight calculations in gaseous substances.

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Homework Statement



A gaseous hydrocarbon weighing 0.185g occupies a volume of 110.cm^3 at 26 celsius and 743mmHg. what is the molecular weight of this compound?

Homework Equations



PV=nRT

The Attempt at a Solution



i have no idea where to start ;(
 
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The molecular weight is in g/mol; you have the mass of the sample, so now you need to find the moles so you can divide them. Rewriting the equation to get n, or the moles, by itself gives you n = PV/RT. Convert everything to the correct units, then plug them into the equation.
 
ohh, i see it now.. many thanks =]
 

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