Answer:
E = 29.7× 10⁻²⁰ j
Explanation:
Given data;
Frequency of light = 4.48 × 10¹⁴ Hz
Energy of photon = ?
Solution:
Formula:
E = h.f
E = energy of photon
h = planck's constant
f = frequency
E = h.f
E = 6.63 × 10⁻³⁴ Kg.m² /s × 4.48 × 10¹⁴ s⁻¹
E = 29.7× 10⁻²⁰ Kg.m²/s²
Kg.m²/s² = j
E = 29.7× 10⁻²⁰ j
POH will be -log[conc of OH]
-log (3.9E-08) = 7.409
pH = 14- pOH
pH = 14 - 7.409
pH = 6.59
Data: molar mass 470 g/mol
Percent composition:
Hg = 85.0%
Cl = 15.0%
Solution:
1) Convert % to molar ratios
A. Base: 100 g
=> Hg = 85.0 g / 200.59 g/mol = 0.4235 mol
Cl = 15.0 g / 35.45 g/mol = 0.4231 mol
B. divide by the higher number and round to whole number
Hg = 0.4325 / 0.4231 = 1.00
Cl = 0.4231 / 0.4231 = 1.00
=> Empirical formula = Hg Cl
2) Find the mass of the empirical formula:
HgCl: 200.59 g/mol + 35.45 g/mol = 236.04
3) Determine how many times is the empirical mass contained in the molecular mass:
470 g/mol / 236.04 = 1.99 ≈ 2
=> Molecular formula = Hg2 Cl2.
Answers:
Empirical formula HgCl
Molecular Formula Hg2Cl2
Answer:
16.0 g; 3.1 mol
Explanation:
(a) Mass of O atoms
Mass = 6.022 × 10^23 atoms × (2.66 × 10^-23 g/1 atom) = 16.0 g
(b) Moles of O atoms
0.050 kg = 50 g
Moles = 50 g × (1 mol/16.0 g) = 3.1 mol
