Question

Рассчитайте массовые доли химических элементов в хлориде магния

Answer 1

Mr(MgCl₂)=24+35*2=94
W(Mg)=24/94 * 100%=25,5%
W(Cl)=70/94*100%=74,5%

Answer 2

Calculation of Mass Fractions in Magnesium Chloride

To calculate the mass fractions of chemical elements in magnesium chloride (MgCl2), we need to determine the molar masses of magnesium (Mg) and chlorine (Cl) and then use stoichiometry to find the mass of each element in the compound.

The molar mass of an element is the mass of one mole of that element. According to the periodic table, the molar mass of magnesium is approximately 24.31 grams per mole (g/mol) The molar mass of chlorine is approximately 35.45 g/mol.

The chemical formula for magnesium chloride is MgCl2, which means it contains one magnesium atom and two chlorine atoms. To calculate the mass fractions, we need to find the mass of each element in one mole of magnesium chloride.

The mass of magnesium in one mole of magnesium chloride can be calculated as follows:

Mass of magnesium = (Number of moles of magnesium) x (Molar mass of magnesium)

Since there is one mole of magnesium in one mole of magnesium chloride, the number of moles of magnesium is 1. Therefore, the mass of magnesium in one mole of magnesium chloride is:

Mass of magnesium = 1 x 24.31 g/mol = 24.31 g/mol

Similarly, the mass of chlorine in one mole of magnesium chloride can be calculated as follows:

Mass of chlorine = (Number of moles of chlorine) x (Molar mass of chlorine)

Since there are two moles of chlorine in one mole of magnesium chloride, the number of moles of chlorine is 2. Therefore, the mass of chlorine in one mole of magnesium chloride is:

Mass of chlorine = 2 x 35.45 g/mol = 70.90 g/mol

To calculate the mass fractions, we need to divide the mass of each element by the total mass of magnesium chloride.

Total mass of magnesium chloride = Mass of magnesium + Mass of chlorine

Total mass of magnesium chloride = 24.31 g/mol + 70.90 g/mol = 95.21 g/mol

The mass fraction of magnesium can be calculated as:

Mass fraction of magnesium = (Mass of magnesium) / (Total mass of magnesium chloride)

Mass fraction of magnesium = 24.31 g/mol / 95.21 g/mol ≈ 0.255

The mass fraction of chlorine can be calculated as:

Mass fraction of chlorine = (Mass of chlorine) / (Total mass of magnesium chloride)

Mass fraction of chlorine = 70.90 g/mol / 95.21 g/mol ≈ 0.745

Therefore, the mass fractions of magnesium and chlorine in magnesium chloride are approximately 0.255 and 0.745, respectively.

Please note that the values provided are approximate and may vary slightly depending on the specific isotopic composition of the elements.