A particular household ammonia solution (d= 0.97g/mL) is 6.8% NH3 by mass.
How many milliliters of this solution should be diluted with water to produce 650 mL of a solution with pH = 11.55?
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i am gettig 5.3 x 10^-10
is that rite or worng
pzl conform ..
No. I don't get that answer.
What did you get for the molarity of the 6.8% NH3 solution? I have 3.88 M.
For a solution to be pH = 11.55, what do you have for the (OH^-)? I have 0.00355 M
first i did was
ph = 11.50
PH= 14-11.50
= 2.5
10^-2.5
= 0.0032 M
Volume - 0.65 L
d=0.97g/mL
Mass %= 6.8%
1000mL= 1L
d=m/v m=d X v
m= 0.97g/mL X 1000mL
m=970g
mNH3 = 970g X 0.068=65.96g of NH3
MM of NH3 = 14g/mol + 3 X 1g/mol=17g/mol
nNH3 = 65.96g/17g/mol
n=3.88mol
[NH3]= 3.88mol/L or M
sooooooooooo
v1 = c2v2/c1
= 0.65 * 0.0032 / 3.88
= 52.35
52350 ml
pzl chk again
thnks
See my response to your second post above and note that I didn't work this problem correctly. I have corrected it there, or at least I worked the other problem correctly and this one follows the same procedure.
To solve the problem, we need to determine the volume of the ammonia solution that needs to be diluted with water to produce a 650 mL solution with a pH of 11.55.
First, let's calculate the amount of NH3 in the original ammonia solution:
Mass of NH3 = Mass of solution × Percent of NH3
Mass of solution = Volume of solution × Density of solution
Volume of solution = Mass of solution / Density of solution
Given:
Density of ammonia solution = 0.97 g/mL
Percent of NH3 = 6.8%
Desired volume of final solution = 650 mL
pH of final solution = 11.55
1. Calculate the mass of the ammonia solution:
Mass of solution = Volume of solution × Density of solution
Mass of solution = 650 mL × 0.97 g/mL = 631.5 g
2. Calculate the mass of NH3 in the ammonia solution:
Mass of NH3 = Mass of solution × Percent of NH3
Mass of NH3 = 631.5 g × 0.068 = 42.972 g
3. Calculate the concentration of NH3 in the solution:
Concentration of NH3 = Mass of NH3 / Volume of solution
Concentration of NH3 = 42.972 g / 650 mL = 0.0661 g/mL
Now, to obtain a solution with a pH of 11.55, you need to dilute the ammonia solution.
The pH of a solution is related to the concentration of hydroxide ions (OH-) in the solution. To increase the pH and make the solution more basic, we need to increase the concentration of hydroxide ions. This can be achieved by diluting with water.
In this case, since the concentration of the ammonia solution is given in grams per milliliter, we need to dilute it in a 1:1 volume ratio to achieve a significant change in pH. This means that for every milliliter of ammonia solution, we need to add an equal volume of water.
So, the volume of the ammonia solution that needs to be diluted with water is equal to the desired volume of the final solution:
Volume of ammonia solution to be diluted = Desired volume of final solution - Volume of water added
Volume of ammonia solution to be diluted = 650 mL - 650 mL = 0 mL
Therefore, you don't need to dilute any ammonia solution with water because the desired volume of the final solution is already 650 mL.
It seems like there might be an error in your calculation of 5.3 x 10^-10. Given the information provided, the solution requires no dilution.