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# Help with a2 chemistry question!!! Watch

1. This is the questions:

[OH–] = 2 × 0.0120 = 0.0240

[H+] = 1 x 10^−14 / 0.0240

= 4.166 × 10–13 OR pOH = 1.62

pH = 12.38

My question is why do you have to multiply the concentration of Calcium Hydroxide by 2 in the first step of the answer?

[OH–] = 2 × 0.0120 = 0.0240

[H+] = 1 x 10^−14 / 0.0240

= 4.166 × 10–13 OR pOH = 1.62

pH = 12.38
3. (Original post by CERC)
This is the question:

[OH–] = 2 × 0.0120 = 0.0240

[H+] = 1 x 10^−14 / 0.0240

= 4.166 × 10–13 OR pOH = 1.62

pH = 12.38

My question is why do you have to multiply the concentration of Calcium Hydroxide by 2 in the first step of the answer?
This is the question:

[OH–] = 2 × 0.0120 = 0.0240

[H+] = 1 x 10^−14 / 0.0240

= 4.166 × 10–13 OR pOH = 1.62

pH = 12.38

My question is why do you have to multiply the concentration of Calcium Hydroxide by 2 in the first step of the answer?
Because there are 2moles of OH in everyone one mole of Ca(OH)2

5. (Original post by CERC)
Because there are 2moles of OH in everyone one mole of Ca(OH)2
Ahhh ok. Thanks for your help!

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