Temperature Of Sugar And Calorimetry Essay

1650 Words 7 Pages
Apparatus

• 1x hot plate
• 1x electronic scales
• 4x 100mL beaker
• 4x glass stirring rod
• 4x thermometer
• 1x chemical spatula
• 500mL of deionised water
• 500g of sugar (sucrose – C12H22O11)
• 100g of salt (NaCl)
• 100g of copper sulphate pentahydrate (CuSO4•5H2O)

Method
1. Fill a 100mL beaker with 50mL of water and then weigh it using electron scales and take note of the mass. Place the beaker on the hot plate, but don’t turn the hot plate on.
2. Place a thermometer in the beaker of water and check the temperature. Make sure the water is at 20°C.
3. Select a solvent to test for solubility first; for the method, sugar (sucrose) will be tested first.
4. Using a spatula, add one scoop of sugar to the beaker
5. Stir the water and sugar with
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Keep adding sugar to the water until no more will dissolve
7. Weigh the beaker containing the dissolved sugar and water. Subtract the mass of the beaker and water from Step 1 from the mass just recorded. This is how many grams of sugar you added.
8. Dispose of the contents of the beaker and rinse it out. Repeat Step 1.
9. Place a thermometer in the beaker of water. Turn on the hotplate and heat the water to 50°C.
10. Repeat Steps 4 – 7
11. Repeat Steps 1 – 7; this time heating the water to 80°C.
12. Repeat Steps 1 – 10, but use other solvents, such as salt or copper sulphate pentahydrate.
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The positive Na+ ions were attracted to the oxygen (negative) end of the water molecules, and the negative Cl- ions were attracted to the hydrogen (positive) end of the water molecules. As an end result, the ionic bond between the sodium and the chloride was broken.

CuSO4(s) ⇔ Cu+2(aq) + SO4-2(aq)
Like the sodium chloride, the copper sulphate was split into its individual ionic components. The positive Cu+2 ions were attracted to the oxygen (negative) end of the water molecules, and the negative SO4-2 ions were attracted to the hydrogen (positive) end of the water molecules.

C12H22O11(s) ⇔ C12H22O11(aq)
As sucrose is not an ionic molecule, but is still a polar molecule, it did dissolve into the water but did not split up. A grain of sugar is actually many molecules of sucrose. Dissolving it into the water split the sugar grain into its individual molecules, but didn’t alter the chemical formula of the sucrose.

Table 3: Grams to Moles (Number of Moles = Mass ÷ Molar Mass)
Solute
Molar Mass (g)
20°C (moles)
50°C (moles)
80°C (moles)
Copper (ii) sulphate
249.7
7.2 x

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