# How to find the mass of a mixture of gases ?

You will need:
• molar mass
• mass of the molecule
• equation Mendeleev-Clapeyron
• periodic table
# 1

If the vessel is a mixture of gases, then calculate the volume of the mixtureand the pressure will not be difficult.The volume of gas equal to the volume of the vessel, since the gases tend to fill out all the information they tank.The pressure gauge is measured.But how to find the mass of a mixture of gases?The problem is easily solved if we know the percentage of gas in the mixture.For example, even in the vessel is 20% carbon dioxide and 80% oxygen.Most jobs require determination of the molar mass of the substance.Therefore, to calculate the molar mass of the mixture need more and relative molecular weights of the gases present, results by the periodic table.For the carbon dioxide that number is 44, and oxygen 32.

# 2

molar mass of the mixture is as follows: 44 * 32 * 0.2 + 0.8.Thus calculated molar mass, can solve the problem of how to determine the molecular weight.For it is nece

ssary to find the molar mass of gas divided by the Avogadro constant, the numerical value of which is Na = 6.3 mol-1.To calculate the mass of gas Do the following mathematical operation: the mass of one molecule multiplied by the number of molecules.However, we must also be able to find the number of molecules of each gas in the vessel.It is possible to do otherwise.For how to calculate the mass of the gas, it is necessary to recall the Mendeleev-Clapeyron equation PV = mRT / M.

# 3

Rearranging the equation, we can obtain a calculation formula to find the mass of gas m = PVM / RT, where M is the molar mass of the gas;R- universal gas constant R = 8,1 J / mol.TO;P - gas pressure;T - the absolute temperature;V - volume of gas.In chemistry there is a certain analogy between the gas mixture and substance solution.After the solution - it is the same mixture, such as water and salt.Wondering how to find the weight of the solution, we arrive at the following conclusion.It is necessary to add water weight and mass of dissolved salts.Similarly, to find the mass of the gas mixture to be summed weight of its constituent gases.

# 4

At the molecular level, the same principle applies.How to find a relative molecular mass of a substance?It is necessary to put the masses of all the atoms that comprise a molecule of the substance.The relative atomic mass of all chemical elements are listed in the same famous periodic table.These table values ​​should be rounded.For example, relative atomic mass of oxygen 16. Thus, gases, liquids, and even the presence of molecules reduces the total weight of components to the summation of the mass constituting the mixture or solution.This addition is called the principle of additive mass.