jika bilangan avogadro besarnya 6 × 10^23 molekul/mol , air 300 ml memiliki jumlah molekul ... a. 10^21 b. 10^22 c. 10^23 d. 10^24 e. 10^25 tolong bantuin jawab

air
Mr = 18 ge/mol
NA = 6×10²³ molekul/mol
V = 300 mL = 300 cm³
ρ = 1 gr/vm³
N = __


massa
ρ = m / V
m = ρ V
m = (1 gr/cm³) (300 cm³) = 300 gr

jumlah mol
n = m / Mr
n = (300 gr) / (18 gr/mol)
n = 100/6 mol

jumlah molekul
N = n NA
N = (100/6 mol) • (6×10²³ molekul/mol)
N = 10^25 molekul ← jwb



cat
1 L = 1 dm³
1 L = 1000 mL
1 dm³ = 1000 cm³

M H₂O = 2(1 g/mol) + 16 g/mol = 18 g/mol
1 mL = 1 cm³

N = n NA
    = (m / M) NA
    = ρV NA / M
    = (1 g/cm³)(3 x 10² cm³)(6 x 10²³ molekul/mol) / (18 g/mol)
    = 10²⁵ molekul