chemistry help pleaseWatch
Ca(OH) + H3PO4 > H2O + Ca3(PO4)2
2. ratio of hydroxide to calcium phosphate 1:1, so moles of phosphate is same as ans 1.
3. rearrange the equation in (1.) moles x molecular mass= mass of phosphate in grams.
Divide 5 g by Ca(OH)2's molar mass to work out the moles of Ca(OH)2. As the stoichiometry of the reaction shows that 1 mol of Ca(OH)2 produces 1 mol of Ca3(PO4)2, you multiply the number of mols you worked out in the first part by Ca3(PO4)2's molar mass to get the answer.
Can you correct the formula of calcium hydroxide in your OP and balance the equation? In the UK a 15 or 16 year old should be able to do this so I am surprised if you can not.
According to your now balanced equation, how many moles of calcium hydroxide reactant are needed to make one mole of calcium phosphate? And do you know the equation linking moles, mass and relative formula mass?
Firstly work out the relative formula mass of calcium hydroxide. This contains one calcium, two oxygens and two hydrogens. Work this out and make sure you understand where the znumbers came from. Post your answer to this bit.