General Chemistry Lab Help!! Here is my data. https://drive.google.com/file/d/0B

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General Chemistry Lab Help!!

Here is my data.

https://drive.google.com/file/d/0B1exMUmFXpFeMkFqREIwVFF1eVk/edit?usp=sharing

Here are the questions.

Total mass of the final solution In adding the mass of initial HCl solution (density of - M HCl is 1.03 g ml), the mass of water (density of water is 1.00 g/mf). and the mass of magnesium Heat required to raise the MgCl2 solution to the maximum temperature assuming that the heat capacity of your final MgCl2 solution is 3.97 J/g degree C (from Pre-Laboratory Question 5) Heat required to raise the calorimeter to the maximum temperature using the value for the heat capacity of the calorimeter as determined in part A of this experiment (from Pre-Laboratory Question 6) Total heat evolved by the reaction by adding the heats required to raise both the solution and the calorimeter to the maximum temperature Heat evolved per mole of Mg Change in enthalpy for the following specific reaction. Be sure to indicate the correct sign (- or +) for the change in enthalpy.

Explanation / Answer

"I think I have to use the equation Q = mc(delta)T"

q = (100 g) (22.8 C) (4.184 J/g C)

The 100 g comes from the 100 mL of HCl solution. We assume the density of the solution is 1.00 g/mol, so 100 mL times 1.00 g/mL = 100 g. The specific heat of the solution is ssumed to be equal to pure water.

q = 9539.52 J

You state that you used 100 g of Mg. I'm going to assume that is a mistake and go with 1.00 g. After all, you only have 0.1 mole of HCl avaliable and it gets used up twice as fast as the Mg does.

1.00 g / 24.305 g/mol = 0.0411438 mol of Mg

9539.52 J / 0.0411438 mol = 231858 J/mol

Three sig figs seems reasonable, so

-232 kJ/mol

Note minus sign for exothermic and note change to kJ/mol

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