Ch.5 - Gases

Tro - Chemistry: A Molecular Approach 4th Edition

Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831Not the one you use?Change textbook

Tro 4th Edition

Ch.5 - Gases

Problem 57

Chapter 5, Problem 57

A 248-mL gas sample has a mass of 0.433 g at a pressure of 745 mmHg and a temperature of 28 °C. What is the molar mass of the gas?

Verified step by step guidance

Convert the temperature from Celsius to Kelvin by adding 273.15 to the Celsius temperature.

Convert the pressure from mmHg to atm using the conversion factor: 1 atm = 760 mmHg.

Use the Ideal Gas Law equation, PV = nRT, to solve for the number of moles (n) of the gas. Remember to convert the volume from mL to L by dividing by 1000.

Calculate the molar mass of the gas by dividing the mass of the gas sample by the number of moles calculated in the previous step.

Ensure all units are consistent and check calculations for accuracy.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ideal Gas Law

The Ideal Gas Law relates the pressure, volume, temperature, and number of moles of a gas through the equation PV = nRT. Here, P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin. This law is fundamental for calculating properties of gases under various conditions.

Molar Mass

Molar mass is defined as the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It can be calculated by dividing the mass of the gas sample by the number of moles present. Understanding molar mass is crucial for converting between mass and moles in chemical calculations.

Gas Laws and Conditions

Gas laws describe the behavior of gases under different conditions of pressure, volume, and temperature. In this problem, the gas sample's conditions (pressure in mmHg and temperature in Celsius) must be converted to appropriate units (atmospheres and Kelvin) to apply the Ideal Gas Law correctly. Familiarity with these conversions is essential for accurate calculations.

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Textbook Question

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