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
Answer:
B. NH₃ (l) dissolves in water to form a solution
Explanation:
A solution is a uniform or homogenous mixture of two or more substances. The components of a solution are the solute and solvent. The solute is the substance that is being dissolved in another substance. The solvent is the substance which dissolves the solute.
Mixing the given solutes in water results innthe following:
A. Helium being an inert gas does not dissolve in water at all. Therefore, no solution is formed.
B. Liquid ammonia is very solution in water. When mixed with water, it dissolves in water to form aqueous ammonia solution. Aqueous ammonia is an alkaline solution of ammonia dissolved in water.
C. Silicon (iv) oxide, SiO₂, is a crystalline solid whichnis completely insoluble in water. Mixing it with water does not result in the formation of a solution.
D. Pentane, C₅H₁₂, is a liquid hydrocarbon substance which is insoluble in water. It does not mix with water to form a solution, rather it forms two separate immiscible layers of liquids.
After 1 half life its half the element
after 2 hl its quarter remaining
after 3 hl its half the quarter which is 1 eighth
after 3 half lifes
The pH of the solution at 25 degree celsius of 1.3 × 10⁻⁶ moles of a sample of Sr(OH)₂ is 10.02.
<h3>How do we calculate pH?</h3>
The pH of any solution gives an idea about the acidic and basic nature of the solution and the equation of pH will be represented as:
pH + pOH = 14
Given that,
Moles of Sr(OH)₂ = 1.3 × 10⁻⁶ mol
Volume of solution = 25mL = 0.025L
The concentration of Sr(OH)₂ in terms of molarity = 1.3×10⁻⁶/0.025
= 5.2×10¯⁵M
Dissociation of Sr(OH)₂ takes place as:
Sr(OH)₂ → Sr²⁺ + 2OH⁻
From the stoichiometry of the reaction 1 mole of Sr(OH)₂ produces 2 moles of OH⁻.
Given that the base is a strong base and that it entirely dissociates into its ions, the hydroxide ion concentration is 5.2×10¯⁵×2 = 1.04×10¯⁴ M.
pOH = -log[OH⁻]
pOH = -log(1.04×10¯⁴)
pOH = 3.98
Now we put this value on the first equation we get,
pH = 14 - 3.98 = 10.02
Therefore, the value of pOH is 10.02.
Learn more about pH here:
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