Question

В кристаллической соде безводной правильно 21,2 г Na 2co3 и 36 г воды на массу приходит. Нужно найти формулу кристаллической соды?

Answer 1

Ответ: Na₂CO₃*10H₂O (кристаллическая сода).

Объяснение:

n(Na₂CO₃) = 21,2 г : 106 г/моль = 0,2 моль

n(H₂O) = 36 г : 18 г/моль = 2 моль

Отношение количества воды к количеству карбоната:

2 : 0,2 = 10

Тогда формула кристаллогидрата:

Na₂CO₃*10H₂O (кристаллическая сода).

Answer 2

Ответ:

Na2CO3*10H2O

Объяснение:

Соотношение элементов

Na2CO3 - 21.2/106=0,2

H2O - 36/18=2

Na2CO3 / H2O - 0.2 /2 - 1/10

Na2CO3*10H2O

Answer 3

Finding the Formula of Anhydrous Sodium Carbonate

To find the formula of the crystalline soda (sodium carbonate), we need to determine the ratio of sodium carbonate to water in the given sample.

According to the information provided, the mass of anhydrous sodium carbonate (Na2CO3) is 21.2 grams, and the mass of water (H2O) is 36 grams.

To find the formula, we need to calculate the molar ratio between sodium carbonate and water.

Calculating the Molar Ratio

To calculate the molar ratio, we need to convert the masses of sodium carbonate and water into moles.

The molar mass of sodium carbonate (Na2CO3) is calculated as follows: - 2 sodium atoms (2 x 22.99 g/mol) = 45.98 g/mol - 1 carbon atom (1 x 12.01 g/mol) = 12.01 g/mol - 3 oxygen atoms (3 x 16.00 g/mol) = 48.00 g/mol

Total molar mass of sodium carbonate = 45.98 + 12.01 + 48.00 = 105.99 g/mol

The number of moles of sodium carbonate can be calculated using the formula: moles = mass / molar mass

Number of moles of sodium carbonate = 21.2 g / 105.99 g/mol = 0.2 mol

The molar mass of water (H2O) is calculated as follows: - 2 hydrogen atoms (2 x 1.01 g/mol) = 2.02 g/mol - 1 oxygen atom (1 x 16.00 g/mol) = 16.00 g/mol

Total molar mass of water = 2.02 + 16.00 = 18.02 g/mol

The number of moles of water can be calculated using the formula: moles = mass / molar mass

Number of moles of water = 36 g / 18.02 g/mol = 2 mol

Determining the Ratio

To find the ratio between sodium carbonate and water, we divide the number of moles of sodium carbonate by the number of moles of water.

Ratio = moles of sodium carbonate / moles of water = 0.2 mol / 2 mol = 0.1

The ratio between sodium carbonate and water is 0.1.

Writing the Formula

The formula of the crystalline soda (sodium carbonate) can be written as Na2CO3 · 10H2O.

Note: The formula indicates that for every 1 mole of sodium carbonate, there are 10 moles of water molecules associated with it.

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