Question

Формула вещества CH4 , V(л) 2,8 ; Найти : M(г/моль) ,n(моль),m(г) , N(молекул)

Answer 1

V =2,8 (л)

М(CH4)=12+4*1=16(г/моль)
n=V/Vm, где Vm - объем газа при н.у. = 22.4 (л/моль)
n=2.8/22.4=0.13 (моль)
m=n*M
m=0.13*16=2.08 (г)
N=Na*n, где Na - число Авагадро =6.02*10^23 (г/моль)
N=6.02*10^23*0.13=0.78*10^23 (молекул)

Answer 2

Formula and Given Values

The formula of the substance is CH4, and the given values are: - V(л) = 2,8

Calculating Molar Mass (M)

To calculate the molar mass (M) of CH4, we need to add up the atomic masses of each element in the formula. The atomic mass of carbon (C) is approximately 12.01 g/mol, and the atomic mass of hydrogen (H) is approximately 1.01 g/mol.

M(CH4) = (1 * M(C)) + (4 * M(H))

M(CH4) = (1 * 12.01 g/mol) + (4 * 1.01 g/mol)

M(CH4) = 16.05 g/mol Therefore, the molar mass of CH4 is 16.05 g/mol.

Calculating the Number of Moles (n)

To calculate the number of moles (n) of CH4, we can use the ideal gas law equation:

n = V / Vm

Where: - V is the volume of the substance (given as 2.8 L) - Vm is the molar volume at standard temperature and pressure, which is approximately 22.4 L/mol for ideal gases.

n(CH4) = 2.8 L / 22.4 L/mol

n(CH4) ≈ 0.125 mol Therefore, the number of moles of CH4 is approximately 0.125 mol.

Calculating the Mass (m)

To calculate the mass (m) of CH4, we can use the formula:

m = n * M

Where: - n is the number of moles (calculated as 0.125 mol) - M is the molar mass (calculated as 16.05 g/mol)

m(CH4) = 0.125 mol * 16.05 g/mol

m(CH4) ≈ 2.00625 g

Therefore, the mass of CH4 is approximately 2.00625 g.

Calculating the Number of Molecules (N)

To calculate the number of molecules (N) in CH4, we can use Avogadro's number, which is approximately 6.022 × 10^23 molecules/mol.

N(CH4) = n * N_A

Where: - n is the number of moles (calculated as 0.125 mol) - N_A is Avogadro's number (approximately 6.022 × 10^23 molecules/mol)

N(CH4) = 0.125 mol * (6.022 × 10^23 molecules/mol)

N(CH4) ≈ 7.5275 × 10^22 molecules

Therefore, the number of molecules in CH4 is approximately 7.5275 × 10^22 molecules.

In summary: - Molar Mass (M): 16.05 g/mol - Number of Moles (n): 0.125 mol - Mass (m): 2.00625 g - Number of Molecules (N): 7.5275 × 10^22 molecules