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1. (Original post by J_riley18)
Okay is 74.093 right?
74 is precise enough.

Now work out the relative formula mass of calcium phosphate. Post your answer.
2. (Original post by TeachChemistry)
74 is precise enough.

Now work out the relative formula mass of calcium phosphate. Post your answer.
Is 182.234 right for calcium phosphate
3. (Original post by J_riley18)
Is 182.234 right for calcium phosphate
No. Look at the formula. There are 3 calcium, 2 phosphorus and 8 oxygen. Make sure you can see how this is the case and give a revised answer.
4. (Original post by TeachChemistry)
No. Look at the formula. There are 3 calcium, 2 phosphorus and 8 oxygen. Make sure you can see how this is the case and give a revised answer.
Is 310 right?
5. (Original post by TeachChemistry)
No. Look at the formula. There are 3 calcium, 2 phosphorus and 8 oxygen. Make sure you can see how this is the case and give a revised answer.
Is 310 right?
6. (Original post by J_riley18)
Is 310 right?
Yes.

Now use the equation below to work out the moles of calcium hydroxide you have in 5 g

Moles X relative formula mass = mass
7. (Original post by TeachChemistry)
Yes.

Now use the equation below to work out the moles of calcium hydroxide you have in 5 g
Moles X relative formula mass = mass
Is 370 g/mol correct
8. (Original post by J_riley18)
Is 370 g/mol correct
You need to work out the moles. You have the mass and you have the relative formula mass from a few posts back. You need to rearrange the equation I have (hopefully) reminded you of.

Try again.
9. (Original post by TeachChemistry)
You need to work out the moles. You have the mass and you have the relative formula mass from a few posts back. You need to rearrange the equation I have (hopefully) reminded you of.

Try again.
Is 1.34 mols correct
10. (Original post by J_riley18)
Is 1.34 mols correct
I cannot see where this number comes from.

You have 5 g and correctly said that the relative formula mass was 74.

Think again.
11. (Original post by TeachChemistry)
I cannot see where this number comes from.

You have 5 g and correctly said that the relative formula mass was 74.

Think again.
I did 5g/mol × 74 = 370 is that right?
12. (Original post by J_riley18)
I did 5g/mol × 74 = 370 is that right?
No. Here's a worked answer because it is bedtime for me now. Make sure you follow it through. Ask tomorrow if unsure.
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This would have been a standard question when I was 14/15 years old

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