Chemistry, 12.08.2020 08:01, minnahelhoor

Al diluir 25 g de sal de mesa en 250ml de agua, ¿En cuántos °C aumenta el punto de ebullición de la disolución formada? ( Ke = 0,52 °C/molal , PM NaCl = 58,44 g/mol)

Answers: 1

Show answers

Answers

answered: AaronMicrosoft15

ΔT= $0.87^{\circ}C$

Explanation:

Para esta pregunta debemos recordar la ecuación que nos permite calcular el aumento ebulliscopico (aumento del punto de ebullición):

ΔT= Kb*m

Donde ΔT es el valor del aumento del punto de ebullición. Kb es la constante ebulloscopica para el agua ( $0.512\frac{Kg~^{\circ}C}{mol}$ ) y m es la molalidad ( $m=\frac{mol}{Kg~
of~
solvente}$ ).

Por lo tanto el primer paso es calcular la molalidad de la solución. Para lo cual tendremos que calcular las moles de sal en los 25 g. Si queremos hacer esto debemos recordar que la formula de sal de mesa es NaCl y que la masa molar de NaCl es 58.44 g/mol. Por lo tanto:

$25~g~NaCl\frac{1~mol~NaCl}{58.44~g~NaCl}~=~0.42~mol~NaCl$

Ahora bien, también debemos saber los Kg de agua en la solución. Por lo que podemos usar la densidad del agua (1 g/mL) para convertir de mL a g y luego hacer la conversión a Kg:

$250~mL\frac{1~g}{1~mL}\frac{1~Kg}{1000~g}~=~0.25~Kg$

Finalmente para el calculo de la molalidad podemos dividir los dos valores:

$m=\frac{0.42~mol}{0.25~Kg}=1.68$

Con el valor de la molalidad se puede calcular ΔT al reemplazar los valores:

ΔT= $1.68~\frac{mol}{Kg}*0.52\frac{Kg~^{\circ}C}{mol}=0.87^{\circ}C$

Si la temperatura de ebullición normal del agua es 100 ºC. Podemos calcular la temperatura final si adicionamos ΔT:

Temperatura final = 100 + 0.87 = 100.87 ºC

Espero sea de ayuda!

answered: Guest

there all right good

explanation:

answered: Guest

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

Other questions on the subject: Chemistry

Chemistry, 22.06.2019 00:40, btcastongia

Which is a difference between molecular compounds and ionic compounds? select the correct answer below: question 5 options: molecular compounds typically form between a metal and a nonmetal, while ionic compounds typically form between nonmetals. molecular compounds result from the transfer of electrons between atoms to form ions, while ionic compounds result from the sharing of electrons between neutral atoms. molecular compounds are formed of discrete, neutral molecules, while ionic compounds are formed of large repeating arrays of opposite charges. molecular compounds have high melting points and high boiling points, while ionic

Answers: 3

continue

Chemistry, 22.06.2019 18:10, sangamlama

The atom fluorine generally will become stable through the formation of an ionic chemical compound by accepting electron(s) from another atom. this process will fill its outer energy level of electrons.

Answers: 1

continue

Chemistry, 23.06.2019 06:20, adrian1742

Describe the magnitude of the buoyant force

Answers: 1

continue

Chemistry, 23.06.2019 06:30, lwattsstudent

When microscope slides are stained to show blood cells, the small red blood cells that appear on the slides are much numerous than the large white blood cells. this supports the concept that

Answers: 1

continue

Do you know the correct answer?

Al diluir 25 g de sal de mesa en 250ml de agua, ¿En cuántos °C aumenta el punto de ebullición de la...