Question

A solution is made by dissolving 4.0 moles of sodium chloride (NaCl) in 2.05 kilograms of water. If the molal boiling point constant for water (Kb) is 0.51 °C/m, what would be the boiling point of this solution? Show all of the work needed to solve this problem

Answer 1

@Photon336 please help

Answer 2

@abb0t

Answer 3

So our first step is to determine how many moles of NaOH we have per kilogram of water
m=4.0 moles/2.05kg
m=?

Answer 4

@lovingod786 ??

Answer 5

Sorry Im here

Answer 6

@taramgrant0543664

Answer 7

1.95 kg?

Answer 8

Yes it would be 1.95 but it would be moles/kg

Answer 9

ok

Answer 10

then what

Answer 11

So our next step is to find our van't Hoff factor which is represented by i

Answer 12

que? Mind speaking english lol

Answer 13

This factor is a constant associated with the dissociation of the solute in the solvent

Answer 14

So NaCl breaks down into two ions Na+ and Cl- meaning that our i value is 2 (keep in mind that it changes for each reaction)

Answer 15

ok

Answer 16

Last step now! We have a formula which is
T=iKbm
T is your change in temperature, i is 2 as found in second step, Kb is given 0.51 and m is what we found in the first step

Answer 17

ok so T= (2)(0.51)(1.95) = 1.989 mol/kg yes?

Answer 18

Yes so the change in temperature is 1.989 (note it's not in mol/kg anymore it is degrees celcius now) to find the boiling point you add this number to the boiling point of water

Answer 19

so 1.989 + 0.51?

Answer 20

The boiling point for water is 100 C so you would add that to the 1.989 the 0.51 is just a constant. For boiling point with water involved you add to 100. If you are doing freezing point with water then you would subtract from zero since 0 is the freezing point.

Answer 21

so 109.989

Answer 22

101.989 celcius would be the boiling point

Answer 23

So thats the answer?

Answer 24

Yes that would be your answer for the boiling point

Answer 25

ok thx

Answer 26

i got another question would you like to help

Answer 27

Of course I can help, start a new post though so I can find everything easier please!

Answer 28

ok