Question

25.3 g of sodium carbonate na2co3 is dissolved in enough water to make 250ml of solution .if na2co3 dissassociates completely molar concof na+and co32- are

Answer 1

Answer on Question #45171 – Chemistry – Inorganic Chemistry

Question

25.3 g of sodium carbonate Na₂CO₃ is dissolved in enough water to make 250 ml of solution. If Na₂CO₃ dissassociates completely molar concentration of Na⁺ and CO₃²⁻ are

Solution

Molar concentration of Na₂CO₃ in the solution:

$$C_{Na_2CO_3} = \frac{m}{M \cdot V} = \frac{25.3 \, g}{105.99 \, \frac{g}{mol} \cdot 0.250 \, L} = 0.955 \, mol/L$$

Chemical equation of sodium carbonate complete dissociation:

$$\mathrm{Na_2CO_3} \leftrightarrow 2 \mathrm{Na^+} + \mathrm{CO_3^{2-}}$$

As is clear from the equation, dissociation of one mole of Na₂CO₃ results in two moles of Na⁺ and one mole CO₃²⁻, so

$$C_{CO_3^{2-}} = C_{Na_2CO_3} = 0.955 \, mol/L$$ $$C_{Na^+} = 2 \cdot C_{Na_2CO_3} = 2 \cdot 0.955 = 1.910 \, mol/L$$

Answer: CNa⁺ = 1.910 mol/L,

$$

C_{CO_3^{2-}} = 0.955 \, mol/L

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