Question

Сколько молей в 4 г. кислорода. Сколько молекул содержится в 111г гидроксида кальция Ca(OH)2 ?Сколько весят3•10 в 20 степени молекул воды? Даю 25 баллов!!! ​

Answer 1

Ответ:

Определим количество вещества азота по формуле:

1)n = V/Vm = 4,48л/22,4л (моль) = 0,2 моль

Найдем N:

N = n*Na = 0,2 моль * 6*10²³ молекул/моль = 1,2 *10²³ молекул

Таким образом в 4,48л азота содержатся 1,2*10²³ молекул.

2) M=111 (г)

M (Ca (OH) 2) = 40+2*16+1*2=74 (г/моль)

n=m/M=111/74=1.5 (моль)

N=n*Na, где Na - число Авагадро = 6.02*10^23 (г/моль)

N=1.5*6.02*10^23=9.03*10^23 (молекул)

3) N(H2O)=3*10^20

--------------------

m(H2O)-?

m(H2O)=M(H2O)*N(H2O) / N(A)

m(H2O)=18*3*10^20 / 6.02*10^23=0.009 g

ответ 0.009 г

Answer 2

Number of moles in 4g of oxygen (O2):

To calculate the number of moles in a given mass of a substance, we can use the formula:

Number of moles = Mass / Molar mass

The molar mass of oxygen (O2) is approximately 32 g/mol. Therefore, the number of moles of oxygen in 4g can be calculated as follows:

Number of moles = 4g / 32 g/mol

Calculating this, we find that there are approximately 0.125 moles of oxygen in 4g. [[1]]

Number of molecules in 111g of calcium hydroxide (Ca(OH)2):

To determine the number of molecules in a given mass of a compound, we need to use the concept of moles and Avogadro's number.

1. Calculate the number of moles of calcium hydroxide (Ca(OH)2) using the formula:

Number of moles = Mass / Molar mass

The molar mass of calcium hydroxide (Ca(OH)2) is approximately 74 g/mol. Therefore, the number of moles of calcium hydroxide in 111g can be calculated as follows:

Number of moles = 111g / 74 g/mol

Calculating this, we find that there are approximately 1.5 moles of calcium hydroxide in 111g. [[2]]

2. Use Avogadro's number to calculate the number of molecules in the given number of moles. Avogadro's number is approximately 6.022 x 10^23 molecules/mol.

Number of molecules = Number of moles x Avogadro's number

Therefore, the number of molecules in 1.5 moles of calcium hydroxide can be calculated as follows:

Number of molecules = 1.5 moles x 6.022 x 10^23 molecules/mol

Calculating this, we find that there are approximately 9.033 x 10^23 molecules in 111g of calcium hydroxide. [[3]]

Weight of 3 * 10^20 molecules of water:

To calculate the weight of a given number of molecules of a compound, we need to use the concept of moles and molar mass.

1. Calculate the number of moles of water (H2O) using the formula:

Number of moles = Number of molecules / Avogadro's number

The given number of molecules is 3 * 10^20. Therefore, the number of moles of water can be calculated as follows:

Number of moles = 3 * 10^20 molecules / 6.022 x 10^23 molecules/mol

Calculating this, we find that there are approximately 0.00498 moles of water.

2. Calculate the weight of the given number of moles of water using the formula:

Weight = Number of moles x Molar mass

The molar mass of water (H2O) is approximately 18 g/mol. Therefore, the weight of 0.00498 moles of water can be calculated as follows:

Weight = 0.00498 moles x 18 g/mol

Calculating this, we find that the weight of 3 * 10^20 molecules of water is approximately 0.0896 grams. [[4]]

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