Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Mole and the Avagadro's Number

Sponsored Links

The SI unit for amount of substance is the mole , defined as

  • the amount of substance that has an equal number of elementary entities as there are atoms in 12 g of carbon-12  ( 12 C -  the isotope of carbon with standard atomic weight 12 by definition).

That number of elementary entities in carbon-12 is the Avogadro constant (number), N A.

N A = 6.022141 10 23 [molecules/mol]

The mole is one of the base units of the SI, and has the unit symbol [ mol] .

Standard volume of 1 mole of an ideal gas at 1 atmosphere and 0°C is 22.414 liters.
See also Molecular Weight - Common Substances


Example:
Number of molecules in 1 mole of hydrogen gas.

Hydrogen gas contains H 2 molecules.  1 mole of a substance is 6.022141*10 23 molecules of the substance.

So; 1 mole of hydrogen gas contains 6.022141*10 23 H 2 -molecules


Example:
Number of molecules in ethyl alcohol

The molecular weight of ethyl alcohol is 46.07 kg/kmol and the number of molecules in 1 kg can be calculated as

n = (1 [kg] / 46.07 [kg/kmol])* 6.022 10 23 [molecules/mol] * 1000 [mol/kmol]

= 1.31*1 0 25 [molecules]

Sponsored Links

Related Topics

Basics

The SI-system, unit converters, physical constants, drawing scales and more.

Related Documents

Air - Molecular Weight and Composition

Dry air is a mixture of gases where the average molecular weight (or molar mass) can be calculated by adding the weight of each component.

Carbon Dioxide Gas - Ideal Properties

Enthalpy, Entropy and Internal Energy of Carbon Dioxide gas.

Gases - Molar Specific Heats

Molar specific heats for some common gases at constant volume.

Hydrocarbons - Melting Point vs. Molecular Weight

Calculate melting point of hydrocarbons from molecular weight (molar mass).

Moist Air - Mole Fraction of Water Vapor

Mole fraction of water vapor is the ratio of water molecules to air and water molecules.

Molecular Weight of Substances

Definition and molecular weight (molar mass) of some common substances.

Nitrogen - Enthalpy, Internal Energy and Entropy vs. Temperature

Enthalpy, internal energy and entropy of Nitrogen as an ideal gas.

Oxygen - Enthalpy, Internal Energy and Entropy vs. Temperature

Enthalpy, internal energy and entropy of oxygen as an ideal gas.

Solutions, Molarity and Dilution

Definitions and examples of how to calculate wt%, molarity and how to prepare dilutions.

Sponsored Links

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.