I think that is A is the answer.
Nitrous acid<span> dissociates as follows:
</span>
HNO₂(s) ⇄ H⁺(aq) + NO₂⁻(aq)
According to the equation, an acid constant has the following form:
Ka = [H⁺] × [NO₂⁻ ] / [HNO₂]
From pH, we can calculate the concentration of H⁺ and NO₂⁻:
[H⁺] = 10^-pH = 10^-2.63 = 0.00234 M = [NO₂⁻]
Now, the acid constant can be calculated:
Ka = 0.00234 x 0.00234 / 0.015 = 3.66 x 10⁻⁴
And finally,
pKa = -log Ka = 3.44
Explanation:
To convert moles to particles or grams to particles, let us have a firm understanding of what a mole is.
A mole is the unit of measuring quantity of particles.
It is the amount of substance that contains the Avogadro's number of particles.
The particle can be atoms, molecules, formula units, electrons, protons, neutrons, etc.
So, to convert from moles to particles;
1 mole of a substance contains 6.02 x 10²³ particles
To convert from grams to particles;
First convert to moles;
number of moles = 
So, 1 mole of a substance contains 6.02 x 10²³ particles
Answer:
Electronegativity generally increases from left to right across a period,
Explanation:
The true statement from the given choices is that electronegativity generally increases from left to right across a period.
Electronegativity is the measure of the relative tendency with which an atom of the element attract valence electrons in a chemical bond.
Across a period electronegativity increases from left to right and decreases down the group.
This is due to reduction in metallic properties as we move across the period from left to right.
You are testing which fertilizer makes the radishes grow the fastest.
factors you should control: sunlight exposure, water amount, fertilizer amount.
Measure: check the rows of radishes to see how much each row has grown in comparison to the others. Whichever row with the healthiest radishes has the best fertilizer.
