When the concentration is expressed in ppm, that means parts per million. It is also equivalent to mg/L. For this problem, we do stoichiometric calculations. We manipulate the units by cancelling like units if they appear in the numerator and denominator side until we come with the amount of solid Ca(OCl)2 needed. The solution is as follows:
40 mg/L * (1 L/1000 mL) * 50 mL * (1 g/1000 mg) * (1 mol OCl⁻/51.452 g) * (1 mol Ca(OCl)₂/ 2 mol OCl⁻) * (142.983 g Ca(OCl)₂/mol) * 0.95 = 2.64×10⁻3 g or 2.64 mg.
Therefore, you would need 2.64 mg of solid Ca(OCl)₂.
The melting point of camphor is 178.4°C which is also the freezing point.
After the unknown substance is added, the freezing point is reduced to 173.6°C.
The freezing point depression is
178.4°C - 173.6°C = 4.8°C
The molar mass of the substance can be found using the equation
Kf m = 4.8
37.7 (0.664 / MW) = 4.8
MW = 5.22 g/mol
A measure for the amount of matter in an object would be grams or kilograms.
the measure of the force of gravity acting on an object would be newtons.
the amount of matter in an object is called mass.
the force of gravity acting upon an object would be called weight.
