1) The depression of the freezing point is a colligative property.
For non ionic compounds it may be calculated with the formula:
ΔTf = Kf * m
Where Kf is the cryoscopic constant of the water = 1.86°C/mol
And m is the molality, m = number of moles of solute / kg of solvent
You have 500.0 g of solvent = 0.5000 kg
And you can calculate the moles in 36.0 g of glucosa dividing by its molar mass:
number of moles = mass in grams / molar mass = 36.0 g / 180.0 g/mol = 0.2 mol
=> m = 0.2 mol / 0.5000 kg = 0.4 m
=> ΔT = 1.86°C/m * 0.4m = 0.744 °C.
Given that the freezing point of pure water is 0.0°C, the new freezing point is 0°C - 0.744 °C = - 0.744°C
Answer: - 0.744 °C
2) Elevation of boiling point is another colligative property.
It is calculate as:
ΔTb = i * Kb * m.
Whre i is van't Hoff constant, which accounts for the number of ions generated in ionic compounds.
Here, you do not have the i constant, but you can tell that each molecule of KCl dissociates into 2 ions (one K+ and one Cl-) which is to say that i = 2.
Kb is the boiling constant of the solvent, which here is water => Kb = 0.512 °C/m.
You also know the boiling point of the solution as 103.07°C. Given that the normal boiling point of pure water is 100.0°C, ΔT is 103.07°C - 100.0 °C = 3.07°C.
Then you can determine the molality, m = ΔTb / (i*Kb) = 3.07°C / (2*0.512°C/m) = 3.00 °C.
Answer: 3.0 °C
Answer:
Noble gases are a unique set of elements in the periodic table because they don't naturally bond with other elements.
Explanation:
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Answer:
The mass is
Explanation:
From the question we are told that
The current supplied is
The time taken is t = 37.0 sec
Generally the charge been deposited on the cathode is mathematically represented as
Substituting values
Generally 1 mole of the lead deposited contains
Then would contain how many moles
Not let say x is the number of moles deposited then
Using this mathematical relation
From the the question we are told that lead is been oxidized to lead 2 oxide which implies that the two electron would be accepted by the lead cation
Hence the number of moles that would be deposited at the cathode is
Now the molar mass of lead is constant with a value
Generally mass is mathematically represented as
For lead
Substituting values
Answer:
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Ice-albedo feedback is a strong positive feedback in the climate system. Warmer temperatures melt persistent ice masses in high elevations and upper latitudes. Ice reflects some of the solar energy back to space because it is highly reflective.
Explanation:
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