Investigating The Relationship Between Relative Molecular...

Wesley College IB Chemistry IA: Energetics Candidate: Jacob Savarirayan Candidate number: 0006120082 Design: Focus problem: Investigating the relationship between the relative molecular mass a primary alcohol and the respective enthalpy of combustion for that alcohol. Independent, dependent, and controlled variables: Variable Manipulating, measuring, or controlling variable Independent variable The primary alcohol used Different alcohols (methanol, ethanol, and 1-propanol) will all be used within their respective spirit burners. Dependent variable The amount (mass) of alcohol burned The dependent variable will be measured by taking readings of both the initial and final masses of the spirit burner (without the cap) thus the change in mass can be calculated. Controlled variable 1 The change in temperature within the water in the metal can will be held constant at a change of 20oc The change in temperature is held constant at +20oC. This will be controlled to the best ability (see step 8, method). This is predominantly controlled to allow for consistency within the energy gained by the 100cm3 of water, and to maintain a consistent error in temperature change. Controlled variable 2 The equipment used The equipment used throughout the experiment will be the same, as will the setup. This will be further controlled by performing every trial within the same approximately 75 minute period, thus eliminating the need to re-setup the apparatus. This control ensures that