You are asked to bring the pH of 0.500 L of 0.450 M NH4Cl to 7.00.
12.0 M NH3
How many drops (1 drop 0.05 mL) of this solution would you use?
What I did, but its incorrect
Using HH equation
I found out NH4 pKa = 9.24 from table
pH = pKa + log [A-] / [HA]
7.00 = 9.24 + log [NH3] / [NH4+]
[NH3] / [NH4+] = 0.00575
n= CV
n NH4+ = (0.450M)(0.500L)
= 0.225 mol
n NH3 = 0.00575 = NH3 / 0.225 mol NH4
= 0.00129375
n=CV
mol NH3 = (12.0M)(V)
0.00129375 mol = (12M)(V)
1.078125x10^-4 L = V
convert to mL
(0.1078mL) (1 drop / 0.05 mL)
= 2.156
= 2.2
Express your answer as an integer.
539 / 250
I worked the problem and came up with 2.16 mL which tells me your 2.156 mL is correct. I think your problem is that if you are to express your answer as an integer, then 2.156 converts to 2
To find an integer expression for the answer, you can divide 539 by 250 and round to the nearest whole number.
539 ÷ 250 = 2.156
Rounding 2.156 to the nearest whole number gives you 2.
Therefore, the integer expression for 539/250 is 2.