Question

1. How many grams are there in 7.5 x 1023 molecules of H2SO4?
2. How many molecules are there in 122 grams of Cu(NO3)2?
3. How many moles in 28 grams of CO2?
4. What is the mass of 3 moles of Fe2O3?
5. How many moles of neon atoms are present in 16.3 L of neon gas at STP?
6. What is the volume 2 mol of chlorine Cl2 gas at STP
7. Find the mass in grams of 2.00 x 1023 molecules of F2.
8. Determine the volume in liters occupied by 14 g of nitrogen N2 gas at STP.
9. What is the relative density ofnitrogen oxide NO2 gas according to air?
10. What is the relative density of oxygen O2 gas according to methane CH4?

Can anyone please explain any of these questions?

Answer 1

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×$10^{23}$ molecules of $H_{2} SO_{4}$?

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×$10^{23}$

∴$\frac{7.5*10^{23} }{6.02*10^{23}}$=1.25 mol(2d.p.)

Lastly, find the grams using the formula $M= \frac{m}{n}$

m=Mn

m=1.25*98

m=122.5g

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In conclusion, use those formula to help you:

$M= \frac{m}{n}$ (which M = molecular mass(atomic mass) m=mass of the substance and n = moles)

Avogadro's constant: $\frac {molecular mass} {6.02*10^{23}} = moles$