[payata]

Hi Guys,

this time, I am practice pH calculations I am stock, at math    I highlight the number with the red color which I do not how to calculate, I hope you can help with that, Thank you in advance!


In short: in taks I need to find the concentration (in g/dm3 units) of an ammonia solution which has a pH of 11.100?




1.584 × 10-6 = 1.75 × 10-5 × (cweak base – 1.2589 × 10-3)
1.584 × 10-6 = 1.75 × 10-5 cweak base – 2.203 × 10-8
1.606 × 10-6 = 1.75 × 10-5 cweak base
cweak base = 0.091773 M

[AWK]

Kb = [OH^-]²/(c-[OH^-])

[payata]

Hi AWK,
Thank you for help, now I know how to find 1.584 × 10-6 , but still, don't know how to find 1.606 × 10-6 

[AWK]

In the second equation, you moved something with a negative sign from the right side of the equation to the left one.