Question

К смеси состоящей из кальция и оксида кальция массой 10 г. добавили воды, при этом выделилось 2,24л. водорода. Определить состав смеси по массе. Очень срочно!!! Пожалуйста!!!

Answer 1

1.n(H2)=2,24/22,4=0,1моль
2. Водород выделяется только при взаимодействии кальция с водой:
Са+2Н2О=Са(ОН)2+Н2
n(H2)=n(Ca)=0,1моль
м(Са)=0,1*40=4 г
м(СаО)=10-4=6 г
3.W(Ca)=4/10=40%
W(CaO)=60%

Answer 2

Problem Analysis

We are given a mixture consisting of calcium and calcium oxide with a total mass of 10 g. When water is added to the mixture, 2.24 L of hydrogen gas is released. We need to determine the composition of the mixture by mass.

Solution

To solve this problem, we need to use the concept of stoichiometry and the ideal gas law.

1. Calculate the number of moles of hydrogen gas released: - We know that 1 mole of any gas occupies 22.4 L at standard temperature and pressure (STP). - Therefore, the number of moles of hydrogen gas released can be calculated as follows: ``` moles of hydrogen gas = volume of hydrogen gas released / volume of 1 mole of hydrogen gas at STP = 2.24 L / 22.4 L/mol = 0.1 mol ```

2. Determine the molar ratio between calcium oxide (CaO) and hydrogen gas (H2) using the balanced chemical equation: ``` CaO + H2O -> Ca(OH)2 ``` - From the balanced equation, we can see that 1 mole of calcium oxide reacts with 1 mole of water to produce 1 mole of calcium hydroxide. - Since 1 mole of calcium hydroxide produces 1 mole of hydrogen gas, the molar ratio between calcium oxide and hydrogen gas is 1:1.

3. Calculate the number of moles of calcium oxide: - Since the molar ratio between calcium oxide and hydrogen gas is 1:1, the number of moles of calcium oxide is also 0.1 mol.

4. Calculate the mass of calcium oxide: - The molar mass of calcium oxide (CaO) is 56.08 g/mol. - Therefore, the mass of calcium oxide can be calculated as follows: ``` mass of calcium oxide = number of moles of calcium oxide * molar mass of calcium oxide = 0.1 mol * 56.08 g/mol = 5.608 g ```

5. Calculate the mass of calcium: - Since the total mass of the mixture is 10 g and the mass of calcium oxide is 5.608 g, the mass of calcium can be calculated as follows: ``` mass of calcium = total mass of mixture - mass of calcium oxide = 10 g - 5.608 g = 4.392 g ```

Answer

The composition of the mixture by mass is approximately: - Calcium oxide (CaO): 5.608 g - Calcium (Ca): 4.392 g

Please note that these values are approximate and may vary slightly due to rounding errors.

I hope this helps! Let me know if you have any further questions.