Question

1. До вапняку масою 12,5 г добавили надлишок розчину оцтової кислоти, при цьому утворився кальцій ацетат масою 15,8 г. Яка масова частка кальцій карбонату зразку вапняку? будь ласка допоможіть(Віддам всі бали(30)​

Answer 1

Объяснение:

CaCO3 + 2 CH3COOH → H2O + CO2 + Ca(CH3COO)2

Answer 2

To find the mass fraction of calcium carbonate in the sample of limestone, we need to calculate the mass of calcium carbonate and then divide it by the total mass of the limestone sample.

Let's assume the mass of the excess acetic acid solution added is x grams.

Given: Mass of limestone = 12.5 g Mass of calcium acetate formed = 15.8 g

To find the mass of calcium carbonate, we need to consider the balanced chemical equation for the reaction between calcium carbonate and acetic acid:

CaCO3 + 2CH3COOH -> Ca(CH3COO)2 + H2O + CO2

From the equation, we can see that 1 mole of calcium carbonate reacts with 2 moles of acetic acid to form 1 mole of calcium acetate. The molar mass of calcium carbonate is 100.09 g/mol.

Using the molar ratio, we can calculate the moles of calcium carbonate:

Moles of calcium carbonate = Moles of calcium acetate formed = Mass of calcium acetate formed / molar mass of calcium acetate

Moles of calcium carbonate = 15.8 g / 158.17 g/mol = 0.1 mol

Since the molar ratio between calcium carbonate and calcium acetate is 1:1, the moles of calcium carbonate formed are equal to the moles of calcium carbonate in the limestone sample.

Now, we can calculate the mass fraction of calcium carbonate:

Mass fraction of calcium carbonate = (Mass of calcium carbonate / Total mass of limestone) * 100

Mass fraction of calcium carbonate = (0.1 mol * 100.09 g/mol) / 12.5 g * 100 = 80.072%

Therefore, the mass fraction of calcium carbonate in the limestone sample is approximately 80.072%.

Please note that this calculation assumes that the reaction goes to completion and there are no other reactions or impurities present in the limestone sample.