Data:
solute: ethylene glicol => not ionization
molar mass of ethylene glicol (from internet) = 62.07 g/mol
solute = 400 g
solvent = water = 4.00 kg
m =?
ΔTf = ?
Kf = 1.86 °C/mol
Formulas:
m: number of moles of solute / kg of solvent
ΔTf = Kf*m
number of moles of solute = mass in grams / molar mass
Solution
number of moles of solute = 400 g / 62.07 g/mol = 6.44 moles
m = 6.44 mol / 4 kg = 1.61 m <-------- molality (answer)
ΔTf = 1.86 °C / m * 1.61 m = 2.99 °C <---- lowering if freezing point (answer)
Answer: -
2.5 moles of calcium atoms are in 2.5 moles of calcium carbonate CaCO₃
Explanation: -
In order to solve such types of problems, the first step would be to write the chemical formula of the compound.
The chemical formula of calcium carbonate = CaCO₃
The chemical symbol of Calcium is Ca.
From the formula of calcium carbonate we can see that
1 mole of CaCO₃ has 1 mole of Ca
2.5 mole of CaCO₃ has 
= 2.5 mol of Ca.
∴2.5 moles of calcium atoms are in 2.5 moles of calcium carbonate CaCO₃
Answer:
Molality, Solvent, Solute, Mole fraction, Molarity.
Explanation:
The expression of concentration that provides the moles of solute per kilograms of solvent is Molality. This in the only expression referred to the solvent.
A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solvent is water. When water is present, it is usually considered the solvent.
A solution is made up of 0.15 grams of sodium chloride in 1 liter of water. For this solution, the Solute is sodium chloride. There can be 1 or more solutes in a solution.
If you place 5 moles of sodium chloride and 4 moles of sucrose into 11 moles of water, the Mole fraction of sodium chloride would be 0.25. The mole fraction is equal to the moles of a substance divided by the total number of moles.
A way to express concentration that provides the moles of solute per liter of solution is Molarity.
Answer:
a substance that dissolves in another substance
Explanation:
a substance into which another substance dissolves
