Assuming we have a 100g sample, the mass of each element is as follows:
C: 74 g
H: 7.4 g
N: 8.6 g
O: 10 g
Next, we calculate the moles of each by dividing the mass of each element by its molar mass:
C: (74 / 12) = 6.17
H: (7.4 / 1) = 7.4
N: (8.6 / 14) = 0.61
O: (10 / 16) = 0.625
Now, we take the smallest value to determine the ratio:
C: 10
H: 12
N: 1
O: 1
Thus, the empirical formula can be expressed as
C10H12NO
From the provided data, the unknown mixture was composed of salt, salicylic acid, and sand. It is understandable that the student suspected the presence of sand, yet scientific experimentation must verify such assumptions. The test involving salt and salicylic acid reveals that salt dissolves in water, while salicylic acid is only slightly soluble, and sand does not dissolve at all. By introducing the unknown into water, the salt would dissolve first, followed by the partial dissolution of salicylic acid. Heating the mixture could allow for the evaporation of salicylic acid, resulting in the remaining salt. If traces of sand were observed in the dissolved sample, it could suggest contamination.
The molecular formula is C6H12O6.
<span>To determine the specific heat of a solid sample, I’d begin by measuring the mass of the solid. Then, I would prepare a sufficient quantity of water at room temperature to fully submerge the solid. This water would go in an insulated container. I'd then heat the solid to a known temperature. Next, I’d record both the temperature of the solid and the water. After that, I'd submerge the heated sample in the water, allowing them to reach thermal equilibrium. I would then note this final equilibrium temperature.
The temperature difference between the heated sample and the equilibrium state indicates the change in temperature of the solid. Given the known mass, initial temperature of the water, and the equilibrium temperature, I can calculate the energy transferred from the solid to the water.
With the mass of the sample, the change in temperature of the solid, and the transferred energy, I have enough information to find the specific heat of the solid sample</span>
