Question

Рассчитайте химическое количество порции воды массой 7,2 г и число содержащихся в ней атомов.

Answer 1

Ответ:

B порции воды массой 7,2 г содержится примерно 0,4 моль воды или около 2,4 x 10^23 атомов

Объяснение:

n=m/M

n=7.2/18=0.4 моль

Число атомов в этой порции воды можно рассчитать, умножив химическое количество на число Авогадро (6,022 x 10^23 атомов/моль):

N=n*N_a

N =0,4 моль * 6,022 x 10^23 атомов/моль ≈ 2,4 x 10^23 атома.

Answer 2

Calculating the Chemical Amount of Water

To calculate the chemical amount of a portion of water with a mass of 7.2 g and the number of atoms it contains, we can use the following steps:

1. Calculate the Number of Moles of Water: - The molar mass of water (H2O) is approximately 18.015 g/mol. - We can use the formula: \[ \text{moles} = \frac{\text{mass}}{\text{molar mass}} \] - Substituting the given mass of water (7.2 g) and the molar mass of water (18.015 g/mol) into the formula will give us the number of moles of water.

2. Determine the Number of Water Molecules: - One mole of water contains Avogadro's number of molecules, which is approximately \(6.022 \times 10^{23}\) molecules/mol. - We can use the relationship: \[ \text{number of molecules} = \text{moles} \times 6.022 \times 10^{23} \] - This will give us the total number of water molecules in the given mass.

Calculation Steps

1. Calculate the Number of Moles of Water: - Using the formula: \[ \text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{7.2 \, \text{g}}{18.015 \, \text{g/mol}} = 0.3999 \, \text{mol} \] - Therefore, the number of moles of water is approximately 0.3999 mol.

2. Determine the Number of Water Molecules: - Using the relationship: \[ \text{number of molecules} = \text{moles} \times 6.022 \times 10^{23} = 0.3999 \, \text{mol} \times 6.022 \times 10^{23} \, \text{molecules/mol} = 2.406 \times 10^{23} \, \text{molecules} \] - Therefore, the given mass of water (7.2 g) contains approximately \(2.406 \times 10^{23}\) water molecules.

Conclusion

The chemical amount of a portion of water with a mass of 7.2 g is approximately 0.3999 moles, and it contains approximately \(2.406 \times 10^{23}\) water molecules.