Answer:
Explanation:
Work function of potassium = 2.29 eV = 3.67 X 10⁻¹⁹ J
So the minimum energy of photon must be equal to 3.67 X 10⁻¹⁹ J .
energy of photon of wavelength λ = hc / λ
where h = 6.67 x 10⁻³⁴
c = 3 x 10⁸
Putting the values in the equation above
6.67 x 10⁻³⁴ x 3 x 10⁸ / λ = 3.67 X 10⁻¹⁹
λ = 6.67 x 10⁻³⁴ x 3 x 10⁸ / 3.67 X 10⁻¹⁹
= 5.452 x 10⁻⁷
= 5452 x 10⁻¹⁰ m
= 5452 A .
Answer:
1859.4 g of ZnCrO₄ in 10.25 moles
Explanation:
First of all, we determine the molecular formula of the compound:
Zinc → Zn²⁺ (cation)
Chromate → CrO₄⁻² (anion)
Zinc chromate → ZnCrO₄
Molar mass for the compound is:
Molar mass of Zn + Molar mass of Cr + (Molar mass of O) . 4 = 181.41 g/mol
65.41 g/mol + 52 g/mol + 16 g/mol . 4 = 181.41 g/mol
Let's apply this conversion factor: 10.25 mol . 181.41 g/mol = 1859.4 g