Measure volume in liters, and moths show amount of substance. Directly it is impossible to transfer liters in a moth, but it is possible to establish ratios between amount of substance and its volume.
Instruction
1. Write down the equation of chemical reaction corresponding to a statement of the problem. Place correctly coefficients. Remember that, according to the law of constancy of structure, the number of the atoms which reacted has to equal to number of the atoms which are formed as a result of reaction.
2. Let you have a gaseous product of V. As Avogadro's law says, under the same conditions the equal volumes contain the same amount of substance of any gas. As a result from Avogadro's law, 1 mol of any gas occupies the same volume.
3. As a rule, tasks in chemistry deal with normal conditions. In this case 1 mol of any gas occupies the molar volume of Vm=22.4 of l/mol. So, to receive number of moths of gas of V, divide this volume into molar: ν=V/Vm. If, substituting numbers in a formula, you specify also dimension, then will see that liters will be reduced, and moths will pass from a denominator into numerator.
4. It is possible to carry out also the return procedure, that is from moths to receive liters. Let there is a gas which amount of substance ν=5 mol. Then the volume of this gas is V = ν ∙ mol Vm=5 ∙ 22.4 l/mol = 112 l. As you can see, here moths were reduced, and liters remained.
5. If the amount of any substance participating in reaction on the equation it is set it is possible to define amount of any other substance from this reaction. For this purpose it is necessary to write down proportions on coefficients. For example, iron hydroxide decomposition reaction: 2Fe (OH)3=Fe2O3+3H2O. 3 molecules of the formed water and 1 molecule of oxide of iron are the share of two molecules of hydroxide. Therefore amounts of substance of hydroxide, oxide and water correspond as 2:1:3. If in a task it is told that 10 mol of oxide of iron were formed, then it is possible to draw a conclusion that 20 mol of hydroxide were taken.
6. If you deal not with gas, and with liquid or a solid body, express at first from volume weight. For this purpose it is necessary to know substance density. Having divided the mass of substance into its molar weight, you will find number of moths.