Chemistry GCSE question

[holidaydreaming]

For all you chemistry buffs!
I’m trying to help my dd with her chemistry hw. Can anyone help explain how we would work question 4a and b out? Thx in advance!

Work out number of moles of Na you have in 24 (2.4?)g of sodium.

From the balances equation, work out how many moles of Na2O you make (half as many, because you have 4 Na on the left, and 2 moles of product on the right).

Work out the mass of that number of moles of Na2O.

Equation: mass (g) = number of moles/ relative mass

Same idea for 4b.
Calculate how many moles you have, and therefore how many moles you make, then convert moles of product back into g.

More reacting mass calculations
The mass of a product or reactant can be calculated using the balanced equation. Follow these steps.
Write out the balanced symbol equation. Underline the two substances you are interested in.
Write the given mass of a substance under its formula.
Work out the total relative formula mass (Mr) for each substance (the one you know and the one you are trying to find out). Write these under their formulae.
Calculate: unknown mass = (known mass ÷ total Mr of known substance) × total Mr of unknown substance.
WORKED EXAMPLE
Calculate the mass of iron (Fe) that can be extracted from 8 g of Fe2O3 in the reaction with carbon.
Step one
2Fe2O3 + 3C →
4Fe + 3CO2
Step two
8 g
? g
Step three
2 × 160 = 320
4 × 56 = 224
Step four
mass of iron formed = (8 ÷ 320) × 224 = 5.6 g

What @MaizeAmaze said

Thanks all. I think we got step one done but we’ve then got a bit stuck. It’s 30 years since I did this so I’m no use so thanks to you all for trying to put us on the right track!