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# Quick Chemistry Question watch

1. Any help would be appriciated!! xx
How many moles of hydroxide ions are present in 25cm3 of an aqueous solution of calcium hydroxide Ca(OH)2 of concentration 0.20mol????
2. mistake/.
3. (Original post by Little Willow)
Any help would be appriciated!! xx
How many moles of hydroxide ions are present in 25cm3 of an aqueous solution of calcium hydroxide Ca(OH)2 of concentration 0.20mol????
The other person is wrong as there are twice as many moles of OH ions as there are Ca ions. Just work out how many moles overall and double it

(concn x volume)/1000 = 0.005 moles CaOH2

x2 = 0.01 moles
4. (Original post by Little Willow)
Any help would be appriciated!! xx
How many moles of hydroxide ions are present in 25cm3 of an aqueous solution of calcium hydroxide Ca(OH)2 of concentration 0.20mol????
No. of moles= vol(cm3)/1000 x concentration
0.20 x 25/1000= 5 x 10^-3
As it is a diprotic base= 5x 10 ^-3 x 2=0.01
5. oh yeah
sorry my mistake
6. Thank you both xxx

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