The Hand Warmer Design Challenge Where does the

The Hand Warmer Design Challenge Where does the heat come from? AP Chemistry: Laboratory Spring 2016

Central Challenge Design a hand warmer that meets the following criteria: 1. Increases in temperature by 20 o. C after salt (ionic compound) is dissolved in 50. 0 m. L water 2. Costs as little as possible to make 3. Uses chemicals that are safe and environmentally friendly

Investigation Timeline • Part 1: Calorimetry Practice • Part 2: Calorimeter Calibration • Part 3: Data Collection & Experimental Procedure

Investigation Timeline • Part 1: Calorimetry Practice • Part 2: Calorimeter Calibration • Part 3: Data Collection & Experimental Procedure

Report Guidelines: Lab Notebook Pages • Pre-lab questions (complete, correct) • DETAILED procedure (numbered steps, materials/equipment, amounts needed) • Data, Observations, & Analysis (mass, T, ΔT) • • Part 1: Calorimetry Practice (Mg. SO 4) Part 2: Calorimeter Calibration Part 3: Experimental Procedure Organized in tables! • Calculations • • Enthalpy (q): hot, cold, calorimeter, solution, reaction Calorimeter constant C ΔHsoln Organized in step by step format! • Post-lab questions (complete, correct)

Report Guidelines: Presentation (10 min) 1. Describe all factors considered to meet criteria 2. Explain rationale for choosing one chemical and not the others Possible Organization: • Overview of experiment & claim • Experimental Evidence + Cost & Safety Analysis • Reasoning to support claim • BONUS: sales pitch