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The affect of elements dissolving on the temperature. By: Monica, Kristin, and Sarah. Purpose and Hypothesis. Purpose: To determine if dissolving a solute affects the temperature. Hypothesis: The temperature would decrease as the amount of solute increased.
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The affect of elements dissolving on the temperature By: Monica, Kristin, and Sarah
Purpose and Hypothesis • Purpose: • To determine if dissolving a solute affects the temperature. • Hypothesis: • The temperature would decrease as the amount of solute increased.
Independent Variable, Levels, and Dependent Variable • The independent variable is the amount of sodium chloride (g). • Levels: • The dependent variable is the temperature.
Constants and procedure Constants: ~amount of water (50 mL) ~ Styrofoam cup ~type of solute ~ temperature sensor Procedure: • Measure 50 mL of water, put it into a Styrofoam cup. • Record starting temperature. • Measure 1 gram of NaCI and add it to the cup. • Record the temperature after 1 minute. • Calculate the change in temperature. • Repeat steps 1-5 using 2 grams, 3 grams, 4 grams and 5 grams. When using CaCl2,repeat steps 1-5 using measurement increments of .2.
Conclusion • As more Sodium Chloride was added, the temperature of the solution decreased. • As more Calcium Chloride was added, the temperature of the solution increased. • The rate for sodium chloride was -.28oC/g. • The rate for calcium chloride was-+2.8oC/g
Why did this happen??? ~When the salt dissolves in water, all bonds break. ~Sodium Chloride bond breaks and becomes sodium and Chloride Ion. ~Water molecules that were attracted to each other break apart. ~Sodium and Chloride Ion are attracted to the water, and create a new bond. ~Energy is absorbed and energy is released. We can measure the chemical energy, by taking the temperature. ~Chemicals absorb energy; endothermic change: decrease in temperature. ~Chemicals lose energy; exothermic change: increase in temperature.