Question

calculate the value of [H30+] from the give [-OH] and label the solution as acidic or basic

A. 2.00*10^-3 M

B. 9.59*10^-9

Answer 1

[H3O+][OH-]=1x10^-14

Answer 2

Can you calculate [H3O+] for A?

Answer 3

walk me through the steps

Answer 4

how do i do that

Answer 5

Substitute the value for OH- and solve for H3O+

Answer 6

You can do it! :)

Answer 7

nope i tried

Answer 8

What did you try?

Answer 9

on my own i dont see a way

Answer 10

i tried doing -log(2.00*10^-3 M)

Answer 11

Why are you using that equation?

Answer 12

That would solve for pOH, but we aren't looking for that now.

Answer 13

Use the equation I gave you.

Answer 14

1x10^-14

Answer 15

i dont know help me and ill folow along

Answer 16

please

Answer 17

[H3O+][OH-] = 1x10^-14
Can you substitute the value for [OH-] given?

Answer 18

im slowly saying no becuae I dont really know

Answer 19

Ok. I will show you.
[H3O+][2x10^-3] = 1x10^-14

Answer 20

Do you see how I did that?

Answer 21

yes

Answer 22

Ok, good. :) Now, can you solve for [H3O+]?

Answer 23

dont let me do this bymyself please. I am pullingmy hair out just foing this problem

im not really savvy in chemistry

Answer 24

I am helping you. This part is the algebra you did in the last problem. You can do it!

Answer 25

Think of it like this:
(2x10^-3)x=1x10^-14

Answer 26

Solve for x.

Answer 27

it it x=1/20000000

Answer 28

Close. I get 1/200000000000 or 5x10^-12

Answer 29

so 5x10^-12is the anwer for A

Answer 30

SOLUTION

Answer 31

(1x10^-14)/(2x10^-3)

Answer 32

Right.

Answer 33

That is the first part for A.

Answer 34

We still need to find whether the solution is acid or basic though.

Answer 35

This you can get using the equation you mentioned before but with [H3O+].

Answer 36

pH=-log[H3O+]
and pH of less than 7 is acidic, greater than 7 is basic

Answer 37

i i meant basic as it is greater than 7

Answer 38

Yes! I get pH =11.3 which is basic :)

Answer 39

now we have to do part b

Answer 40

Ok.It is the same exact procedure. Can you try?

Answer 41

[H3O+][ 9.59*10^-9] = 1x10^-14

Answer 42

is it

Answer 43

Godd!

Answer 44

*good haha

Answer 45

(9.59*10^-9)x = 1x10^-14

Answer 46

Yup

Answer 47

x=1.04275*10^-6

Answer 48

Me too!

Answer 49

and it is acidic

Answer 50

so it is 1.04*10^-6

Answer 51

right

Answer 52

Right! You did it! :)

Answer 53

and it is acid

Answer 54

Correct.

Answer 55

and it 1.04*10^-6 to three sig figs like 1.04 or is it just 1

Answer 56

1.04 is 3 sig figs

Answer 57

(2.33*10^-10)x=1x10^-14

Answer 58

can you help me solve that

Answer 59

i got 0.0000429185

Answer 60

right

Answer 61

Yup!

Answer 62

Or 4.29x10^-5

Answer 63

and it is acidic

Answer 64

Is the 2.33x10^-10 the [H3O+]?

Answer 65

or [OH-]?

Answer 66

pH=-log[H3O+]

Answer 67

NO SRRY IT IS OH-

Answer 68

Then yup :)

Answer 69

i meant acidic

Answer 70

rigt

Answer 71

Yes, acidic