Answer: C) 0.020 m
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
where,
n = moles of solute
= weight of solvent in g
Mole fraction of 
is = 
i.e. moles of is present in 1 mole of solution.
Moles of solute 
=
moles of solvent (water) = 1 - = 0.99
weight of solvent =
Molality =
Thus approximate molality of in this solution is 0.020 m
<u>Answer:</u> The correct answer is Option A.
<u>Explanation:</u>
Electronegativity is defined as the tendency of an atom to attract the shared pair of electrons towards itself whenever a bond is formed.
This property increases as we move from left to right across a period because the number of charge on the nucleus gets increased and electrons are attracted more towards the nucleus.
This property decreases as we move from top to bottom in a group because the electrons get add up in the new shells which make them further away from the nucleus.
Thus, the correct answer is Option A.
There are eight protons in an Oxygen's nucleus.
Answer:
Particles of matter possess energy called kinetic energy.
Solid cannot be compressed, but gases are highly compressible.
The Kinetic energy of molecules of gases is very large & solids the least.
On heating a sublimable liquid, the molecules break free & escape from the surface of the solid directly into vapour.
Particles of matter move more rapidly on the application of heat
Answer:
333.7g of antifreeze
Explanation:
Freezing point depression in a solvent (In this case, water) occurs by the addition of a solute. The law is:
ΔT = Kf × m × i
Where:
ΔT is change in temperature (0°C - -20°C = 20°C)
Kf is freezing point depression constant (1.86°C / m)
m is molality of solution (moles solute / 0.5 kg solvent -500g water-)
i is Van't Hoff factor (1, assuming antifreeze is ethylene glycol -C₂H₄(OH)₂)
Replacing:
20°C = 1.86°C / m × moles solute / 0.5 kg solvent × 1
5.376 = moles solute
As molar mass of ethylene glycol is 62.07g/mol:
5.376 moles × (62.07g / 1mol) = <em>333.7g of antifreeze</em>.
