Question

I'll give you brainliest, if your answer is right :) Element A is in group 1A with a molar mass of 10 g/mol Element B is in group 7A with a molar mass of 30g/mol
a, A (solid) and B (gas) undergoes a combination reaction. Write the balanced chemical equation.
b, How many grams of B2 are needed to form a 2.5 M solution of AB with a volume of 250 mL?

Answer 1

Mass of B₂ = 18.75 g

Further explanation

Given

Element A and element B

Required

The reaction

mass of B₂

Solution

The balanced equation :

2A(s) + B₂(g) ⇒2AB(s)

mol AB :

= Molarity x Volume

= 2.5 M x 0.25 L

= 0.625

From the equation, mol ratio of B₂ : AB = 1 : 2, so mol B₂ :

= 1/2 x mol AB

= 1/2 x 0.625

= 0.3125

Mass B₂ (Molar mass = 2x30 g/mol=60 g/mol)

= mol x molar mass

= 0.3125 x 60 g/mol

= 18.75 g