Quick chemistry question?!?

Question

How many moles of ions are in one mole of Ca(OH)2 ?

How many moles of electrons in one mole of OH- ions?

From OCR Foundation Chemistry, Jan 07

Couls someone please tell me the answer and how they worked it out ?

Answer 1

There are 3 moles of ions: 1 mole of Ca++, and 2 moles of OH-.

Do you want all the electrons or the outer shell electrons of OH-? 1 mole of OH- has 10 moles of electrons, 8 from oxygen, 1 from hydrogen and 1 to make electronegative (usually borrowed from another hydrogen).

Answer 2

well in Ca(OH)2 there r one Ca2+ and two OH- ions.
that is a total of three ions are present.
thus as there is one mole of Ca(OH)2 there are three moles of ions present.

and in OH- oxygen has 8 electrons and hydrogen has 1 plus the added electron as there i a (-1) sign, thus a total of 10 electrons are there.
now as there is one mole of OH- there are 10 moles of electrons.

Answer 3

Ca(OH)2 isan ionic compound of Ca2+ and OH-; so you get 3 ions for each formula unit.

OH- contains 8 electrons from O, 1 from H, and 1 more for the overall negative charge.

that's all! Don't let anyone kid you into imagining this stuff is hard!

Answer 4

Xg of Fe = 40g Fe2O3 This is just a way of putting down what you know. Then look at the moles which is the big number at the start of a Fe or any symbol which you would then write out as 2mol Fe = 1mol Fe2O3 Then figure out the formula mass of each by looking up the mass of each element in the data booklet and timesing it first by the number of mols: Fe x 2 And then by the lower case numbers: Fe x 2 + O x 3 (the number of mols of iron oxide is just one) I don't have a data booklet but it would be Mass of Fe x 2 = mass of Fe x 2 + mass of O x 3 Then to finish off X = (mass of Fe x 2) x ( 40/ mass of Fe x 2 + mass of O x 3) This should give you the answer :)