The answer is a total of 74,844 calories.
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.
Solution:
Molality measures the concentration of a solute in a solution, defined by the amount of solute per specific mass of solvent.
Thus,
Molality = moles of solute / kg of solvent.
Therefore, kg of solvent = moles of solute / molality.
moles of solute = mass / molar mass
= 25.31 g / 101.1 g/mole
= 0.2503 mole.
kg of solvent = 0.2503 mole / 0.1982 m
= 1.263 kg
= 1263 g.
This is the final answer.
<span>(NH4)2CO3 -> 96.09 g/mol
(6.995g ammonium carbonate)(1mol ammonium carbonate/ 96.09 g ammonium carbonate) = 0.072796 mol ammonium carbonate
In this calculation, the unit 'grams' cancels out as it's present in both the numerator and the denominator, leading to 'mol' being the remaining unit.
Examining the formula (NH4)2CO3, it can be interpreted as:
2 mol (NH4) + 1 mol (CO3) = 1 mol (NH4)2CO3
This means every mole of ammonium carbonate yields one mole of carbonate ions and two moles of ammonium ions.
(0.072796 mol ammonium carbonate) = (0.072796 mol carbonate ion) + (0.363981 mol ammonium ion) </span>
Step 1: Convert density from g/mL to g/L; 0.807 g/mL is equivalent to 807 g/L. Step 2: Calculate Moles of N₂; Density = Mass / Volume, or Mass = Density × Volume. Plugging in values, Mass = 807 g/L × 1 L gives us Mass = 807 g. Similarly, Moles = Mass / M.mass, which leads to Moles = 807 g / 28 g.mol⁻¹, giving us Moles = 28.82 moles. Step 3: Apply the Ideal Gas Law to determine Volume of gas occupied; P V = n R T, thus V = n R T / P. Remember to convert temperature to Kelvin (25 °C + 273 = 298 K). Hence, V = (28.82 mol × 0.08206 atm.L.mol⁻¹.K⁻¹ × 298 K) ÷ 1 atm, resulting in V = 704.76 L.
