Mass of iron = 1.0 g.Hence, the required order of increasing masses is one atom of silver 10²³ atoms of C< one-gram atom of nitrogen.

The chemical formula of copper sulphite crystals is CuSO₄ .5H₂O .
According to the data, Percentage of Cu = 25.45 % , Percentage of H₂O = 36.07 % 
Percentage of SO₄ = 100 − ( 25.45 + 36.07 ) = 100 − 61.52 = 38.48 % 
Since the law of constant composition is true, the percentage composition of the other sample of copper sulphite crystals must also remais the same Now, 100 g of copper sulphate crystals contain Cu = 25.45 g. 
∴ 50 g of copper crystals contain \(C u=\frac{(25.45 g)}{(100 g)} \times(40 g)=10.18 g .\)

1 carat = 200 mg, 
∴ 5 carat = 1000 mg = 1g
Hence, he should subtract 1 g from the weight of the ring to get the weight of gold.

The atomic mass of each He is 4.003, to be precise. That means the group of each atom is 4.003 amu. Then the 52 u of He has 52/4.003, which is 12.99 means 13. So, 52 u of He has 13 atoms.

Volume of a drop of water = 0.05 mL
Mass of a drop of water  = volume \(\times\) density
= ( 0.05 mL ) \(\times\)(1.0g / mL)
= 0.05 g
Gram molecular mass of water  ( H₂O ) = 2\(\times\)1 + 16 = 18 g ;
18 g of water = 1 mol
\(\therefore\) 0.05 g of water = \(\frac{1 mol}{(18 g)}\)\(\times\) ( 0.05 g )
= 0.0028 mol
\(\because\) 1 mole of water conmtains molecules = 6.022 \(\times\)10²³
0.0028 mole of water  will contain molecules
= 6.022 \(\times\)10²³\(\times\)0.0028 = 1.68 \(\times\)10²¹ molecules

Calculation of molecular formula
Empirical formula mass =
 \(2\times 56+3\times 16=160\)
\(n=\frac { molecular \ formula }{ empirical \ formula \ mass } =\frac { 160 }{ 160 } =1\)
\(\therefore Molecular\ formula={ A }_{ 2 }{ B }_{ 3 }\)

OK, assuming it is 93% by mass then we should work with 100 g of solution a 93% by mass solution will have 93 g of H₂SO₄ and 7 g of H₂O
moles H₂SO₄ = mass / molar mass = 93 g / 98.086 g/mol = 0.948148 moles
mass H₂O = 7 g = 0.007 kg
molality = moles solute / kg solvent
= 0.948148 mol / 0.007 kg
= 135 m ~ 140 m (2 sig figs)
Now
total volume of 100 g of solution = mass / density
= 100 g / 1.84 g/ml
= 54.35 ml
= 0.05435 L
molarity = moles solute / litres solution
= 0.98148 mol / 0.05435 L
= 18 M