Question

1.If you used a Yeti Vacuum Insulated Tumblert instead of a styrofoam cup for the calorimeter, would the value of Hf MgO(s) be higher or lower? Explain. 2. Comment on the accuracy of your results by discussing the percent error. Was your experimental result greater or less than expected? What one specific factor might reasonably explain your percent error? How would the factor affect the result (would it make your experimental value too large or too small?)? My percentage error is 11.10% The expected: -601600 j/mol Experimental: -534840 j/mol 3. When ammonium chloride is dissolved in water, the following is observed: 73.9 kJ + NH4CI(s)> NH4Cl(aq). Is the water hotter or colder after the ammonium chloride dissolves? Explain why in terms of enthalpy differences between NH4CI(s) and NH4Cl(aq) and also heat exchange between the system and the surroundings.

Answer 1

Question 1.

In a vacuum Insulated Tumbler, the pressure will decrease (where the volume and no. of moles of the gas are the same) compared to that in a styrofoam cup.

According to Gay-Lussac's law: At constant volume and no. of moles of the gas, the pressure of the gas is directly proportional to its temperature.

As a result, the temperature of the gas does also decrease.

Hence, the value of Hf MgO(s) would be lower.

Answer 2

Question 1.

In a vacuum Insulated Tumbler, the pressure will decrease (where the volume and no. of moles of the gas are the same) compared to that in a styrofoam cup.

According to Gay-Lussac's law: At constant volume and no. of moles of the gas, the pressure of the gas is directly proportional to its temperature.

As a result, the temperature of the gas does also decrease.

Hence, the value of Hf MgO(s) would be lower.