Question

How many molecules are present in 18.25g of HCl?
( Atomic masses of : H = 1u, Cl = 35.5u)

Answer 1

Answer:

Mass of HCl = 18.25 gm

Molar mass of HCl = 36.5 g/mol

Mass of water = 500 gm

= 0.5 kg

No. of moles of HCl;

equals fraction numerator Mass space of space HCl over denominator Molar space mass space of space HCl end fraction

equals fraction numerator 18.25 over denominator 36.5 end fraction

equals 0.5 space mol

Molality is,

equals fraction numerator No. space of space moles over denominator Mass space of space solvent space in space kg end fraction

equals fraction numerator 0.5 over denominator 0.5 end fraction

equals 1 space straight m

Molality of solution is 1 m.