The answer to the question is C
Answer:
En el caso del sodio, la valencia es 1, ya que tiene un solo electrón de valencia, si pierde un electrón se queda con el último nivel completo.
Explanation:
Grupo de la tabla periódica Electrones de valencia
Grupo 14 (IV) (Grupo del carbono) 4
Grupo 15 (V) (Grupo del nitrógeno ) 5
Answer:
<em>When salt is dissolved in water</em>, many physical properties change, among them the so called colligative properties:
- The vapor pressure of water decreases,
- The boiling point increases,
- The freezing point decreases, and
- Osmotic pressure appears.
Explanation:
Colligative properties are the physical properties of the solvents whose change is determined by the number of particles (moles or ions) of the solute added.
The colligative properties are: vapor pressure, boiling point, freezing point, and osmotic pressure.
<u>Vapor pressure</u>:
The vapor pressure is the pressure exerted by the vapor of a lquid over its surface, in a closed vessel.
The vapor pressure increases when a solute is added, because the presence of the solute causes less solvent molecules to be near the surface ready to escape to the vapor phase, which means that the vapor pressure is lower.
<u>Boiling point</u>:
The boiling point is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure. Since we have seen that the vapor pressure of water decreases when a solute occupies part of the surface, now more temperature will be required for the water molecules reach the atmospheric pressure. So, the boiling point increases when salt is dissolved in water.
<u>Freezing point</u>:
The freezing point is the temperarute at which the vapor pressure of the liquid and the solid are equal. Since, the vapor pressure of water with salt is lower than that of the pure water, the vapor pressure of the liquid and solid with salt will be equal at a lower temperature. Hence, the freezing point is lower (decreases).
<u>Osmotic pressure</u>:
Osmotic pressure is the additional pressure that must be exerted over a solution to make that the vapor pressure of the solvent in the solution equals the vapor pressure of the pure solvent. This additional pressure is proportional to the concentration of the solute: the higher the salt concentration the higher the osmotic pressure.
Mole fraction<span> is another way of expressing the concentration of a solution or mixture. It is equal to the </span>moles<span> of one component divided by the total </span><span>moles.
mass CH4O = 0.270 (51) = 13.77 g methanol
water = 51 - 13.77 = 37.23 g water
Hope this answers the question. Have a nice day.</span>
The vapour pressure of the solution is 23.4 torr.
Use <em>Raoult’s Law</em> to calculate the vapour pressure:
<em>p</em>₁ = χ₁<em>p</em>₁°
where
χ₁ = the mole fraction of the solvent
<em>p</em>₁ and <em>p</em>₁° are the vapour pressures of the solution and of the pure solvent
The formula for vapour pressure lowering Δ<em>p</em> is
Δ<em>p</em> = <em>p</em>₁° - <em>p</em>₁
Δ<em>p</em> = <em>p</em>₁° - χ₁<em>p</em>₁° = p₁°(1 – χ₁) = χ₂<em>p</em>₁°
where χ₂ is the mole fraction of the solute.
<em>Step 1</em>. Calculate the <em>mole fraction of glucose
</em>
<em>n</em>₂ = 18.0 g glu × (1 moL glu/180.0 g glu) = 0.1000 mol glu
<em>n</em>₁ = 95.0 g H_2O × (1 mol H_2O/18.02 g H_2O) = 5.272 mol H_2O
χ₂ = <em>n</em>₂/(<em>n</em>₁ + n₂) = 0.1000/(0.1000 + 5.272) = 0.1000/5.372 = 0.018 62
<em>Step 2</em>. Calculate the <em>vapour pressure lowering</em>
Δ<em>p</em> = χ₂<em>p</em>₁° = 0.018 62 × 23.8 torr = 0.4430 torr
<em>Step 3</em>. Calculate the <em>vapour pressure</em>
<em>p₁</em> = <em>p</em>₁° - Δ<em>p</em> = 23.8 torr – 0.4430 torr = 23.4 torr
