Question

Кальциевую стружку массой 4,0 г прокалили на воздухе а затем бросили в воду.При растворении стружки в воде выделилось 560 мл газа,который практически не растворим в воде. 1)запишите уравнение реакции 2)определите на сколько граммов возраста масса стружки при прокалывании 3)рассчитайте состав кальциевой стружки в массовых процентах

Answer 1

1. 2Ca + O2= 2CaO
     CaO + H2O= Ca(OH)2
     Ca + H2O=
2. n(Ca)=m(Ca)/M(Ca)=4/40=0.1моль
     

Answer 2

Reaction Equation and Mass of Calcium Shavings

1) The reaction equation for the reaction between calcium shavings and water can be represented as follows:

Ca + 2H2O → Ca(OH)2 + H2

This equation shows that calcium reacts with water to produce calcium hydroxide and hydrogen gas.

2) To determine the mass of the calcium shavings before the reaction, we need to use the stoichiometry of the reaction. From the balanced equation, we can see that 1 mole of calcium reacts with 2 moles of water to produce 1 mole of hydrogen gas. The molar mass of calcium is approximately 40.08 g/mol.

Given that 560 mL of gas was produced, we need to convert this volume to moles using the ideal gas law. However, we need additional information such as the temperature and pressure to perform this calculation. Could you please provide the temperature and pressure at which the gas was collected?

Composition of Calcium Shavings in Mass Percent

3) To calculate the composition of calcium shavings in mass percent, we need to know the mass of calcium in the shavings and the total mass of the shavings.

Unfortunately, the mass of the calcium shavings before the reaction was not provided in the question. Without this information, it is not possible to calculate the composition of the calcium shavings in mass percent.

If you have the mass of the calcium shavings, please provide it, and I will be happy to assist you further in calculating the composition.