K because parent atoms are always larger than their cations(positively charged atoms)
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 .
Explanation:
Lime is added to lower the acidity of lakes when pH levels go too low.
Acidic environment is harmful to aquatic ecosystems. Acidity causes some minerals, such as phosphorus and calcium, in the water to become unavailable to aquatic organisms like plants and fishes ( This means the water hardness is reduced). The low nutrients cause stress and death in the aquatic environment lowering biodiversity. Applying lime raises the pH to neutral levels and improves the health of the aquatic life in the lake. This also improves economic activities in the lake like fishing.
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Answer:
pH = 11.95≈12
Explanation:
Remember the reaction among aqueous acetic acid (
) and aqueous sodium hydroxide (NaOH)

First step. Need to know how much moles of the substances are present
= 0.0025 mol NaOH
0.003 mol NaOH *
/ 1 mol NaOH = 0.003 mol CH_3COOH[/tex]
NaOH is in excess. Now, how much?
0.003 mole NaOH - 0.0025 mole NaOH = 0.0005 mole NaOH
Then, that amount in excess would be responsable for the pH.
Third step. Know the pH
Remember that pH= -log[H+]
According to the dissociation of water equilibrium
Kw=[H+]*[OH-]= 10^(-14)
The dissociation of NaOH is
NaOH -> 
Now, concentration of OH^{-}[/tex] would be given for the excess of NaOH.
[OH-]= 0.0005 mole / 0.055 L = 0.00909 M
Careful: we have to use the total volumen
Les us to calculate pH
![pH= -log [H+]\\pH= -log \frac{K_w}{[OH-]} \\pH= 11.95](https://tex.z-dn.net/?f=pH%3D%20-log%20%5BH%2B%5D%5C%5CpH%3D%20-log%20%5Cfrac%7BK_w%7D%7B%5BOH-%5D%7D%20%5C%5CpH%3D%2011.95)