A solution of 32.0 grams of NaOH in 800.0 grams of water. A solution of 686 grams of SiCl4 in 2450 grams of toluene, C6H6CH3

Answer 1

1. Weight of NaOH: 32 g

molecular weight of NaOH is 40 g/mol

volume or weight of water is 800ml or 800g = 0.8L or 0.8 kg

Molarity =?

M=n (moles)/V (L) where moles of Na = w/mw =32/40 = 0.8 moles

M= 0.8/0.8 L = 1M

Therefore, Molarity of NaOH is 1M.

Similarly, Molality (m) = moles of solute/kilograms of solvent

Substitute the above values into the formula

Molality (m) of NaOH solution = 0.8 moles/ 0.8 kg

= 1.0 moles / kg

2. Weight of SiCl4: 684 g (Solute)

molecular weight of SiCl4 is 169.9 g/mol

moles of SiCl4 = w/mw = 684 g/169.9 g/mol = 4.025 moles

Weight of Toluene: 2450 g = 2.45kg (solvent)

molecular weight of Toluene is 92.14 g/mol

Molality (m) = moles of solute/kilograms of solvent

Substitute the above values into the formula

Molality (m) of SiCl4 solution = 4.025 moles/ 2.45kg

= 1.642 moles / kg