please answer question #2 fully and explain why. thank you! Post-Lab Assessment

Question

please answer question #2 fully and explain why. thank you!

Post-Lab Assessment Questions: (10 points) 1. pts) Compare your results for the molar heat of your salt (kJ/mol) to the literature value. What is your percent error? Try to give three reasons why your value (kl/mol) may be different from the tabulated values, 2. (2 pts) In 1819, French physicists Dulong and Petit found experimentally that for many solids at room temperature, c 3R (R gas constant in SI units). Show that Dulong-Petit's rule is in agreement with the specific heat capacities of metals in the table. Explain why the specific heat capacity of magnesium is roughly twice as large as the one of titanium, and why the specific heat capacities of lead and gold are nearly identical 3. (3 pts) write the net ionic equation for the reaction between hydro chloric acid and aqueous sodium hydroxide reaction. How would the temperature change and the calculated heat of neutralization vary if the concentration of the acid and the base used in this experiment will

Explanation / Answer

The average molar specific heat at constant pressure for all metals in table is approximately equal to
or near to 25. J mole-1oC-1
the heat required to raise the temperature of a sample of metal depends only on how many molecules
the sample contains, and not on the mass of an individual molecule.
Magnesium = 1.023 J/g oC * 24.305 g/mol = 24.864  J mole-1oC-1
aluminium = 0.897 J/g oC * 26.981g/mol = 24.201  J mole-1oC-1
titanium = 0.524 J/g oC * 47.867 g/mol = 25.082 J mole-1oC-1
Iron =0.449 J/g oC * 55.485 g/mol = 24.912 J mole-1oC-1
copper = 0.385 J/g oC * 63.546 g/mol = 24.465 J mole-1oC-1
silver = 0.235 J/g oC * 107.8682 g/mol = 25.349  J mole-1oC-1
lead = 0.130  J/g oC * 207.2 g/mol = 26.936 J mole-1 oC-1   
gold = 0.129 J/g oC * 196.966 g/mol = 25.408  J mole-1 oC-1   

Specific heat capacity is the amount of heat required to raise the temperature of the 1 mole of substance.
As you can see the molar mass of magnesium is twice that of titanium, that means there are double
times of moles in titanium when compared with magnesium. So, the amount heat required to raise
1 mole of magnesium is twice that of titanium. This is the reason why the specific heat of titanium is
double that of magnesium.

The molar masses of lead and gold are pretty close , so they have approximately same number of moles
to be heated , which makes them have same specific heat capacity.

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