Question

при растворении 180 грамм известняка в избытке азотной кислоты выделилось 34.27 литров углекислого газа.определите массовую долю карбоната кальция в данном образце известняка.Помогите плиз очень надо))

Answer 1

СaCO3 +2HNO3= Ca(NO3)2 +CO2 +H2O 

 

n(CO2) = V / Vm = 34.27 /22.4=1.53моль 
n(CO2) = n(CaCO3) 
m(CaCO3) = n x M = 1.53 моль x 100 г/моль = 153 г 

ω = m(в-ва) х 100% / m(смеси)

ω(CaCO3) = 153 г х 100% / 180 г или 85%

Answer 2

Calculating the Mass Fraction of Calcium Carbonate in Limestone

To determine the mass fraction of calcium carbonate in the given sample of limestone, we can use the stoichiometry of the reaction between calcium carbonate and nitric acid, which produces carbon dioxide gas.

The balanced chemical equation for the reaction is: CaCO3(s) + 2HNO3(aq) → Ca(NO3)2(aq) + CO2(g) + H2O(l)

From the given information, we know that 180 grams of limestone (calcium carbonate) were reacted with an excess of nitric acid, resulting in the production of 34.27 liters of carbon dioxide gas.

Calculation Steps

1. Convert Liters of CO2 to Moles: We need to convert the volume of carbon dioxide gas to moles using the ideal gas law. 2. Use Stoichiometry to Find Moles of CaCO3: Once we have the moles of CO2, we can use the stoichiometry of the reaction to find the moles of calcium carbonate reacted. 3. Calculate Mass Fraction: Finally, we can calculate the mass fraction of calcium carbonate in the limestone sample.

Calculation

1. Convert Liters of CO2 to Moles: - Using the ideal gas law, the number of moles of CO2 can be calculated as: ``` n = PV/RT ``` Where: - P = pressure (assuming standard pressure) - V = volume of CO2 (34.27 L) - R = ideal gas constant - T = temperature (assuming standard temperature)

- After converting the volume of CO2 to moles, we will have the moles of CO2 produced in the reaction.

2. Use Stoichiometry to Find Moles of CaCO3: - From the balanced chemical equation, we know that 1 mole of calcium carbonate produces 1 mole of carbon dioxide. Therefore, the moles of CO2 produced will be equal to the moles of calcium carbonate reacted.

3. Calculate Mass Fraction: - The mass fraction of calcium carbonate in the limestone sample can be calculated using the formula: ``` Mass Fraction = (Mass of CaCO3 / Total Mass of Sample) * 100% ```

Conclusion

By following these steps, we can determine the mass fraction of calcium carbonate in the given sample of limestone.