What is the molar mass of a covalent compound if 0.486 g of it is dissolved in 25.0 ml of water and produces a freezing temperature of -0.40 °c?

Answer is: the molar mass of a covalent compound is 90.4 g/mol.

m(compound) = 0.486 g.
m(water) = 25 mL · 1 g/mL = 25 g ÷ 1000 g/kg = 0.025 kg.
ΔT = 0°C - (-0.40°C) = 0.40°C.

Kf(H₂O) = 1.86°C/m.

M(compound) = Kf · m(compound) / m(water) · ΔT.
M(compound)= 1.86°C/m · 0.486 g / (0.025 kg · 0.4°C).
M(compound) = 90.4 g/mol.

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation:

law of conservation of matter