The freezing point depression is calculated through the equation,
ΔT = (kf) x m
where ΔT is the difference in temperature, kf is the freezing point depression constant (1.86°C/m), and m is the molality. Substituting the known values,
5.88 = (1.86)(m)
m is equal to 3.16m
Recall that molality is calculated through the equation,
molality = number of mols / kg of solvent
number of mols = (3.16)(1.25) = 3.95 moles
Then, we multiply the calculated amount in moles with the molar mass of ethylene glycol and the answer would be 244.9 g.
All of these properties are known as physical properties.
Physical properties are such that they are measured without changing the composition of the of the matter which is under consideration. For example, the melting point of a substance may be tested without changing its composition. The change is also reversed easily. Physical properties are used to describe and observe matter. The other type of properties are chemical properties, which require the composition of a substance to be changed for them to be measured.
The quantities you have to know are the molar masses and the molecular stoichiometric ratios. The solution for this problem is as follows:
Mass Percent of Iodine = (Mass of Iodine/Mass of NaBr and KI)*100
Mass of NaBr = 1 mol NaBr * 102.89 g/mol = 102.89 g
Mass of KI = 0.3 mol KI * 166 g/mol = 49.8 g
Mass of KI = 0.3 mol KI * 1 mol I/1mol KI * 1 mol I₂/2 mol I * 253.81 g/mol = 38.07 g
Mass %I₂ = 38.07/(102.89+49.8) * 100 = <em>24.9%</em>
Someone. or something will get hurt
Answer:
Explanation:
The formula of density is:
If the formula is rearranged for volume, it becomes:
The mass of the platinum is 38.5 grams.
The density is 21.5 grams per cubic centimeter.
Substitute the values into the formula.
Divide. Note that the grams (g) will cancel each other out.
Round to 2 decimal places (hundredth place). The 0 in the thousandth place tells us to leave the 9 in the hundredth place.
The volume is about <u>1.79 cubic centimeters.</u>