Answer:
Option E is the correct one
Explanation:
K₂Cr₂O₇ → Potassium dichromate
A ionic salt which its molar mass is 294.18 g/m
It is composed by 2 mol of K, 2 mol of Cr and 7 mol of O
2 mol of K = 78.2 g
2 mol of Cr = 104 g
7 mol of O = 112 g
In 294.2 g of compound we have __78.2 g K __ 104 g Cr ___ 112 g O
Let's calculate the percent
(78.2 / 294.2) .100 = 26.59% K
(104 / 294.2) .100 = 35.35% Cr
(112 / 294.2) . 100 = 38.06 % O
Answer:
(3) 345 nm
Explanation:
<u>Given:</u>
Average C-C bond energy = 347 kJ/mol
<u>To determine:</u>
Wavelength of photon that can break a C-C bond
<u>Calculation:</u>
The energy (E) of a photon is related to its wavelength (λ) by the Planck's equation:

where h = Planck's constant = 6.626*10⁻³⁴ Js
c = speed of light = 3*10⁸ m/s


λ = 3.45*10⁻⁷ m
Since 1 nanometer (nm) = 10⁻⁹ m
The calculated wavelength corresponds to 345 nm
Use the PV = nRT equation T is in Kelvins = 31 + 273 = 304 K
P(0.5) = (2.91)(0.0821)(304)
P(0.5) = 72.6289
P = 145.25 atm or 1.45x10^2 atm
Answer:
The standard enthalpy of formation of HgO is -90.7 kJ/mol.
Explanation:
The reaction between Hg and oxygen is as follows.

From the given,
Molar mass of HgO = 216.59 g/mol
Mass of HgO decomposed = 18.5 g
Amount of heat absorbed = 7.75 kJ
From the reaction,
The standard enthalpy of formation = 
During the decomposition of 1 mol of HgO , 90.7 kJ of energy absorbed.
For the formation of 1 mol of HgO , 90.7 kJ of energy is release
Therefore, the enthalpy of formation of mercury(II)Oxide is -90.7 kJ/mol
Answer:
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