Experiment Set Up

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• Published : February 9, 2013

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First hand investigation of the Dissolution of Solutes
Background Information
Molar heat of solution
* The molar heat of solution of a substance is the heat absorbed when one mole of the substance dissolves in a large excess of water. It is expressed in kJ/mol. * The specific heat of water is a constant, with a value of 4.18 J/ g*oC. AIM: To determine the molar heat of solution for two different solids Equipment:

* A calorimeter (made using 2 Styrofoam cups with a cardboard lid) * Electronic balance
* Measuring cylinder
* Thermometer
* Ammonium nitrate (NH4NO3)
* Sodium carbonate (Na2CO3)
* Stirrer/Straw

Risk assessment

Wear safety glasses when using chemicals to protect your eyes Wash your hands if you spill the chemicals to your hands
Do not use the thermometer to stir the dissolve the solid as it is easily breakable.

Method
1. Set up the equipment as shown in the diagram
2. Measure accurately the mass of 100ml of tap water. Record this value and any other measurements in the data table. Add the water into the Styrofoam calorimeter. 3. Find and record the initial temperature of the water

4. Accurately measure 15g of solid ammonium nitrate and dissolve in the water using the stirre. 5. Measure and record the final temperature of the solution. Find the difference between the initial and final temperature and record in the data table 6. Rinse out the calorimeter and dry thoroughly and repeat the experiment using about 15g of Sodium carbonate. Data table

| Ammonium nitrateNH4NO3| Sodium carbonateNa2CO3|
Mass of cup +water(g)| | |
Mass of cup (g)| | |
Mass of water (g)| | |
Mass of chemical + container(g)| | |
Mass of container(g)| | |
Mass of chemical(g)| | |
Initial water temperature (oC)| | |
Final water temperature (oC)| | |
Change in water temperature (oC)| | |
Calculating the molar heat of solution
1. Use the formula Q = mcT calculate...