Question

какую формулу имеет кристаллогидрат сульфата меди, если при прокаливании кристаллогидрата массой 500г была получена безводная соль массой 320г? сколько процентов воды содержится в составе кристаллогидрата?

Answer 1

Спрашивай чего не поймешь 

Answer 2

Formula of Copper Sulfate Hydrate

The formula of a hydrate compound indicates the number of water molecules associated with each formula unit of the compound. In the case of copper sulfate hydrate, the formula can be represented as CuSO4 · xH2O, where x represents the number of water molecules.

To determine the formula of the hydrate, we can use the given information about the mass of the hydrate and the mass of the anhydrous salt obtained after heating.

Let's assume that the mass of the copper sulfate hydrate is M grams, and the mass of the anhydrous salt obtained is N grams.

According to the law of conservation of mass, the mass of the water lost during heating is equal to the difference between the mass of the hydrate and the mass of the anhydrous salt:

Mass of water lost = Mass of hydrate - Mass of anhydrous salt

In this case, the mass of the hydrate is 500 grams, and the mass of the anhydrous salt is 320 grams.

Mass of water lost = 500 g - 320 g = 180 g

This means that during the heating process, 180 grams of water were lost from the hydrate.

To find the number of water molecules associated with each formula unit of the hydrate, we need to convert the mass of water lost to moles. The molar mass of water (H2O) is approximately 18 g/mol.

Number of moles of water lost = Mass of water lost / Molar mass of water

Number of moles of water lost = 180 g / 18 g/mol = 10 mol

Since each mole of water contains 6.022 x 10^23 water molecules (Avogadro's number), we can calculate the number of water molecules lost:

Number of water molecules lost = Number of moles of water lost * Avogadro's number

Number of water molecules lost = 10 mol * 6.022 x 10^23 molecules/mol = 6.022 x 10^24 molecules

Therefore, the formula of the copper sulfate hydrate is CuSO4 · 10H2O, indicating that each formula unit of the hydrate contains 10 water molecules.

Percentage of Water in the Hydrate

To calculate the percentage of water in the hydrate, we need to determine the mass of water in the hydrate and divide it by the mass of the hydrate, then multiply by 100.

The mass of water in the hydrate can be calculated by subtracting the mass of the anhydrous salt from the mass of the hydrate:

Mass of water in the hydrate = Mass of hydrate - Mass of anhydrous salt

Mass of water in the hydrate = 500 g - 320 g = 180 g

The percentage of water in the hydrate can be calculated as follows:

Percentage of water = (Mass of water in the hydrate / Mass of hydrate) * 100

Percentage of water = (180 g / 500 g) * 100 = 36%

Therefore, the copper sulfate hydrate contains approximately 36% water by mass.