An experiment was performed to determine the molar volume of O2 generated when determining the percentage of KClO3 in the unknown sample “Sabre.” The decomposition reaction performed would see a heterogeneous mixture break into O2 and KClO so that the molar volume and percent mass could be calculated. About .3g of the unknown Sabre was added to a tube which was sealed and attached to a O2 collector. The tube was heated until the KClO3 was dehydrated and turned into a solid completely. Using the collected data, the average molar volume of O2 was determined to be 22.4 L/mol while the average percent KClO3 in the unknown sample Sabre was 75.9 %.