Question

Задача с использованием понятия"доля" 1.Определить массовые доли элементов (в%)в соединение карбоната кальция (CaCO3) 2.В раствор,массой 500г с массовой долей соли 15% добавили ещё 40г соли. Рассчитайте массовую долю соли в полученном растворе . Помогите пожалуйста)))

Answer 1

1)

Mr(CaCO3) = 40 +12+48 = 100

w(Ca) = 40/100 *100% = 40%

w(C) = 12/100 *100% = 12%

w(O) = 48/100*100% = 48%

2)

500 * 15/100 = 75 г - столько соли было в растворе до добавления

75 +40 = 115 г соли стало в растворе

500 +40 = 540 - масса раствора после добавления соли

115/540 *100% = 21.3% - массовая доли соли в полученном растворе

Answer 2

Mass Percent Calculation for Calcium Carbonate (CaCO3)

To determine the mass percent of elements in a compound, we need to know the molar masses of the elements involved. The molar mass of calcium (Ca) is approximately 40.08 g/mol, carbon (C) is approximately 12.01 g/mol, and oxygen (O) is approximately 16.00 g/mol.

The formula for calcium carbonate is CaCO3, which means it contains one calcium atom, one carbon atom, and three oxygen atoms.

To calculate the mass percent of each element in calcium carbonate, we can use the following formula:

Mass percent of an element = (Number of atoms of the element × Molar mass of the element) / Molar mass of the compound × 100%

For calcium (Ca): - Number of atoms of calcium (Ca) = 1 - Molar mass of calcium (Ca) = 40.08 g/mol

Mass percent of calcium (Ca) = (1 × 40.08 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100%

For carbon (C): - Number of atoms of carbon (C) = 1 - Molar mass of carbon (C) = 12.01 g/mol

Mass percent of carbon (C) = (1 × 12.01 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100%

For oxygen (O): - Number of atoms of oxygen (O) = 3 - Molar mass of oxygen (O) = 16.00 g/mol

Mass percent of oxygen (O) = (3 × 16.00 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100%

Let's calculate the mass percent of each element in calcium carbonate:

Mass percent of calcium (Ca) = (1 × 40.08 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100% = 40.04%

Mass percent of carbon (C) = (1 × 12.01 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100% = 12.00%

Mass percent of oxygen (O) = (3 × 16.00 g/mol) / (40.08 g/mol + 12.01 g/mol + (3 × 16.00 g/mol)) × 100% = 47.96%

Therefore, the mass percent of calcium in calcium carbonate is approximately 40.04%, the mass percent of carbon is approximately 12.00%, and the mass percent of oxygen is approximately 47.96%.

Calculation of Mass Percent in a Solution

In the given problem, we have a solution with a mass of 500 g and a salt with a mass percent of 15%. An additional 40 g of the same salt is added to the solution.

To calculate the mass percent of the salt in the resulting solution, we need to consider the total mass of the solution after adding the additional salt.

The initial mass of the salt in the solution can be calculated using the mass percent formula:

Mass of the initial salt = Mass of the solution × Mass percent of the salt / 100%

Mass of the initial salt = 500 g × 15% / 100% = 75 g

After adding 40 g of the same salt, the total mass of the salt in the solution becomes:

Total mass of the salt = Mass of the initial salt + Mass of the additional salt

Total mass of the salt = 75 g + 40 g = 115 g

To calculate the mass percent of the salt in the resulting solution, we can use the following formula:

Mass percent of the salt = Total mass of the salt / Total mass of the solution × 100%

Mass percent of the salt = 115 g / (500 g + 40 g) × 100%

Mass percent of the salt = 115 g / 540 g × 100% ≈ 21.30%

Therefore, the mass percent of the salt in the resulting solution is approximately 21.30%.

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