Question

Задачаесли 31 г железа взаимодействует с серой при условии что массовая доля использования железа составляет 90%, то в результате реакции образуются сульфид феруму.Якои массы?

Answer 1

Узнаём массу железа который реагирует 
31*0,9=27,9 грамм
Делаем уровнение реакции.
Fe + S -> FeS

Вышитываем количество железа в молях.
Формула n=m/M
n=27,9 / 56 =0,4982

сокращаем до сотых 
n= 0.5 моль.
Т.к. по реакции видно что коэффиценты Fe и FeS одинаковы и равны 1 то
n(Fe) = n (FeS) = 0.5 моль
Считаем массу FeS по обратной формуле
m=n*M
m= 0,5* (56+32) = 44 грам. - это ответ

Answer 2

Reaction of Iron with Sulfur

When 31 grams of iron interacts with sulfur, and the mass fraction of iron used is 90%, the resulting reaction forms iron sulfide. To calculate the mass of iron sulfide formed, we can use the concept of the law of definite proportions.

The law of definite proportions states that a chemical compound always contains exactly the same proportion of elements by mass. In this case, the mass of iron sulfide formed can be calculated based on the mass of iron used and the stoichiometry of the reaction.

Calculation

Given: - Mass of iron (Fe) = 31 grams - Mass fraction of iron used = 90%

To find: - Mass of iron sulfide (FeS) formed

Solution

First, we calculate the actual mass of iron used in the reaction: - Mass of iron used = 90% of 31 grams - Mass of iron used = 0.90 * 31 grams - Mass of iron used = 27.9 grams

Next, we need to determine the stoichiometry of the reaction between iron and sulfur to find the mass of iron sulfide formed. The balanced chemical equation for the reaction is:

Fe + S → FeS

From the balanced equation, it is clear that 1 mole of iron reacts with 1 mole of sulfur to produce 1 mole of iron sulfide.

The molar mass of iron (Fe) is approximately 55.85 g/mol, and the molar mass of sulfur (S) is approximately 32.07 g/mol. Therefore, the molar mass of iron sulfide (FeS) is approximately 87.92 g/mol.

Using the concept of molar mass and stoichiometry, we can calculate the mass of iron sulfide formed: - Number of moles of iron used = Mass of iron used / Molar mass of iron - Number of moles of iron used = 27.9 grams / 55.85 g/mol - Number of moles of iron used ≈ 0.499 moles

Since the reaction between iron and sulfur occurs in a 1:1 ratio, the number of moles of iron sulfide formed is also approximately 0.499 moles.

Finally, we can calculate the mass of iron sulfide formed: - Mass of iron sulfide formed = Number of moles of iron sulfide * Molar mass of iron sulfide - Mass of iron sulfide formed ≈ 0.499 moles * 87.92 g/mol - Mass of iron sulfide formed ≈ 43.88 grams

Answer

Therefore, in the given reaction conditions, approximately 43.88 grams of iron sulfide are formed.