Answer:
I cannot give you all the answer but I can help you to solve those.
Explanation:
The first question:
How many grams are there in 7.5× molecules of
?
So we need to find the molecular mass first, use your periodic table,
And then we can find out 2+32+16×4=98 g/mol
Then, we need to find how many moles, by using Avogadro's constant:
Avogadro's constant: 1 mole = 6.02×
∴=1.25 mol(2d.p.)
Lastly, find the grams using the formula
m=Mn
m=1.25*98
m=122.5g
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In conclusion, use those formula to help you:
(which M = molecular mass(atomic mass) m=mass of the substance and n = moles)
Avogadro's constant: