ure carbon tetrachloride, CCl4, freezes at-23.00 ⁰C and has a kf of 29.8⁰C/m. The latest lot has a freezing point of-23.43⁰C. What is the molality of impurities in thesolvent? If the impurity is largely hexachloroethane, C2Cl6, how many grams of this impurity arethere per kg of CCl4?Once the mass of the impurity is determined, calculate the mass % purity:

Answers

Answer 1
Answer:

Answer:

a) grams of this impurity per kg of CCl4 = 3.416 g/kg of solvent.

b) mass purity % = 99.66%

Explanation:

Given, the freezing point of pure CCl₄ = - 23°C

Presence of impurities lowers the freezing point to - 23.43°C

The freezing point depression constant, Kբ = 29.8°C/m

The lowered freezing point is related to all the parameters through the relation

ΔT = i Kբ × m

where ΔT is the lowered freezing point, that is, the difference between freezing point of pure substance (T⁰) and freezing point of substance with impurities (T).

i = Van't Hoff factor which measures how much the impurities influence/affect colligative properties (such as freezing point depression) and for most non-electrolytes like this one, it is = 1

Kբ = The freezing point depression constant = 29.8°C/m

m = Molality = ?

T⁰ - T = i Kբ m

- 23 - (-23.43) = 1 × 29.8 × m

m = 0.43/29.8 = 0.0144 mol/kg

Them we're told to calculate impurity of the CCl₄

we convert the Molality to (gram of solute)/(kg of solvent) first

Solute = C₂Cl₆

Molar mass = 236.74 g/mol

So, (molality × molar mass) = (gram of solute)/(kg of solvent)

(gram of solute)/(kg of solvent) = 0.0144 × 236.74 = 3.416 (gram of solute)/(kg of solvent)

Mass purity % = (1000 g of pure substance)/(1000 g of pure substance + mass of impurity in 1000 g of pure substance)

1000 g of solvent contains 3.416 grams of impurities

Mass purity % =100% × 1000/(1003.416)

Mass purity % = 99.66 %


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Si tomas 100ml de una solución de Nacl 4m y se disuelve en 200ml utilizando el mismo solvente ¿cuál será la nueva concentración?

Answers

Respuesta:

2 m

Explicación:

Paso 1: Información provista

  • Volumen inicial (V₁): 100 mL
  • Concentración inicial (C₁): 4 m
  • Volumen final (V₂): 200 mL
  • Concentración final (C₂): ?

Paso 2: Calcular la concentración de la solución final

Queremos perparar una concentración diluida a partir de una concentrada. Podemos calcular la concentración de la solución diluida usando la regla de dilución.

C₁ × V₁ = C₂ × V₂

C₂ = C₁ × V₁ / V₂

C₂ = 4 m × 100 mL / 200 mL = 2 m

On the pH scale, a 7 indicates _____.
a base
an acid
neutrality

Answers

The correct answer is:

neutrality

on the pH scale 7 is neutral above 7 is basic and below 7 is acidic.

Explanation:

The pH is an example of how acidic/basic water is. The scale goes from 0 - 14, with 7 being neutral, pH of less than 7 designates acidity, whereas a pH of greater than 7 intimates a base. pH is really a pattern of the relative amount of free hydrogen and hydroxyl ions in the water.pH is a measure of how acidic/basic water is.

It is neutral because, at this pH, the molar concentrations of Hydroxide and Hydronium are same, therefore the substance is not a base nor an acid.

Final answer:

On the pH scale, a 7 represents neutrality. It is not considered acidic nor basic, but instead, it represents a balanced solution, such as pure water.

Explanation:

On the pH scale, a 7 indicates neutrality. This means that the solution is neither acidic nor basic. The pH scale ranges from 0 to 14, with 7 being the midpoint. Solutions with a pH less than 7 are considered acidic, while those with a pH greater than 7 are considered base or alkaline. So, a pH of 7 is indicative of a perfectly balanced solution, like pure water.

Learn more about pH scale:

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Renewable energy resources such as wind andsolar energy have an advantage because they
cannot be depleted.
Agree or disagree

Answers

Answer:

Agree

Explanation:

Renewable energy resources are advantageous because they cannot be depleted with active usage.

  • Renewable resources are resources that can replenished easily and quickly as they are being used up in the ecosystem.
  • Solar energy from the sun is inexhaustible and readily available.

Non-renewable energy resource cannot be replenished as they are being used in nature.

Such resources must be conserved.

Why graphite can rub off the pencil onto the paper

Answers

Graphite is an extremely soft material and is formed in layers as well.This combination of traits allows for the graphite to scrape off of the pencil tip and onto the paper.

Jose times how long sugar takes to dissolve in warm water. He conducts four trials of his experiment. What should he conclude from his data?Trial Time
1 30 seconds
2 32 seconds
3 10 seconds
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Sugar does not dissolve in water.
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His experiment has very low precision.

Answers

Answer:

His experiment has very low precision

Explanation:

Precision is how close the answers are together. The answers are increasing in time. So, this makes sence. None of the answers are similar to one another.

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Answers

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