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Investigate how the amount of salt that dissolves in water changes with temperature.Equipment: Thermometer, Scale, Beaker, Bunsen Burner, Tripod,Give method and give a results table - amount of salt in grams and temperature of water.

User Syed Rafay
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The fisrt step is to look at the expected solubility of NaCl in water. The expected solubility, at 25°C, is 35.9 g/100 ml, which means we expect 35.9 g of NaCl to be dissolved in 100ml of water. To make things easier, we can work with a water volume of 100ml.

The next step is to fill the beaker with a 100 ml of water, registering the room temperature (probably very close to 25°C). Then we can weight some amount of NaCl and add it to the beaker while stirring, untill all NaCl is dissolved.

We should do this until we reach the point that some NaCl is left at the bottom of the beaker. This means we have reached the solubility at that temperature.

We can proceed with the experiment by increasing the temperature. It's always good to increase it the same amount. Let's say we increase it from 25°C to 30°C. We will then do the same thing: weight some amount of salt, add it to the beaker and stirr. When we reach the point that some NaCl is left at the bottom again, we know its solubility in 30°C.

We can do this for several temperatures, and then construct a graph relating temperature and solubility. What we expect is that the solubility of NaCl will increase with temperature, as the blue curve in the graph below shows.

To set the experiment, we will use the Bunsen Burner to warm up the beaker with water over the tripod. The thermometer will be used to control the temperature whenever needed. The scale will be used to measure the amount of NaCl that is being dissolved in water (we measure it before we put it in the beaker).

Investigate how the amount of salt that dissolves in water changes with temperature-example-1
Investigate how the amount of salt that dissolves in water changes with temperature-example-2
User Roych
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