An aqueous solution of 4.57 M H2SO4 has a density of 1.25 g/mL. Calculate the molality of this solution

The molality is 5.7 molal

Explanation:

Step 1: Data given

Molarity of H2SO4 = 4.57 M ( = 4.57 mol/L)

Density of the solution = 1.25 g/mL

Molar mass of H2SO4 = 98.09 g/mol

Step 2: Calculate mass of solution

Suppose we have 1L (= 1000 mL) of solution

Mass of the solution = 1.25 g/mL * 1000 mL

Mass of the solution = 1250 grams

Step 3: Calculate mass H2SO4

In 1L of a 4.57 M solution we have 4.57

Mass H2SO4 = moles H2SO4 * molar mass H2SO4

Mass H2SO4 = 4.57 moles * 98.09 g/mol

Mass H2SO4 = 448.3 grams

Step 4: Calculate mass solvent

Mass solvent = mass solution - mass H2SO4

Mass solvent = 1250 grams - 448.3 grams

Mass solvent = 801.7 grams

Step 5: Calculate molality

Molality = moles H2SO4 / mass solvent

Molality = 4.57 moles / 0.8017 kg

Molality = 5.7 molal

The molality is 5.7 molal

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.