EXPERIMENT 7:
EXPERIMENT 7:
PERCENTAGE OF OXYGEN IN KClO3
Introduction: In this experiment you will determine the percentage of oxygen in potassium chlorate. You will calculate the theoretical value from the chemical formula and compare your experimental value to the theoretical value.
Background: When potassium chlorate (KClO3) is heated, it undergoes chemical decomposition. Oxygen gas (O2) is given off and potassium chloride (KCl) remains as the residue. The equation for the decomposition of potassium chlorate is:
2 KClO3 (s) 2 KCl (s) + 3O2 (g)
Other metal chlorates behave similarly when heated; forming oxygen gas and the corresponding metal chloride. The reaction may be speeded by adding some MnO2 catalyst. Metal chlorate Metal chloride + oxygen
In this experiment a weighed quantity of potassium chlorate is heated. The oxygen formed in the reaction is driven off and the mass of the residue (KCl) is measured. These two quantities, the mass of the original sample of potassium chlorate and the mass of the KCl, allow us to determine the amount of oxygen in the original sample. If a catalyst is used, it will remain unaffected and its weight can be subtracted. The experimental percentage of oxygen in the sample of KClO3 is calculated by using this equation.
Experimental % oxygen = Mass of oxygen lost x 100 Mass of KClO3
The theoretical value of the % oxygen in potassium chlorate is calculated from the formula KClO3 with a molar mass = 122.6 g/mol.
Frequently it is interesting – and instructive - to determine the percent error of an experimental determination. The theoretical percentage of oxygen is used as the accepted value when we calculate the percent error according to this formulation.
Percentage Error = | experimental value – accepted value | x 100 accepted value
The numerator of this equation can be positive or negative – meaning the
PERCENTAGE OF OXYGEN IN KClO3
Introduction: In this experiment you will determine the percentage of oxygen in potassium chlorate. You will calculate the theoretical value from the chemical formula and compare your experimental value to the theoretical value.
Background: When potassium chlorate (KClO3) is heated, it undergoes chemical decomposition. Oxygen gas (O2) is given off and potassium chloride (KCl) remains as the residue. The equation for the decomposition of potassium chlorate is:
2 KClO3 (s) 2 KCl (s) + 3O2 (g)
Other metal chlorates behave similarly when heated; forming oxygen gas and the corresponding metal chloride. The reaction may be speeded by adding some MnO2 catalyst. Metal chlorate Metal chloride + oxygen
In this experiment a weighed quantity of potassium chlorate is heated. The oxygen formed in the reaction is driven off and the mass of the residue (KCl) is measured. These two quantities, the mass of the original sample of potassium chlorate and the mass of the KCl, allow us to determine the amount of oxygen in the original sample. If a catalyst is used, it will remain unaffected and its weight can be subtracted. The experimental percentage of oxygen in the sample of KClO3 is calculated by using this equation.
Experimental % oxygen = Mass of oxygen lost x 100 Mass of KClO3
The theoretical value of the % oxygen in potassium chlorate is calculated from the formula KClO3 with a molar mass = 122.6 g/mol.
Frequently it is interesting – and instructive - to determine the percent error of an experimental determination. The theoretical percentage of oxygen is used as the accepted value when we calculate the percent error according to this formulation.
Percentage Error = | experimental value – accepted value | x 100 accepted value
The numerator of this equation can be positive or negative – meaning the