Answer:
The answer to your question is letter b) He and Ne
Explanation:
Elements that have similar properties are placed in the same group in the periodic table.
So
A C and F These elements do not have similar properties because C is in group 4A and F is in group 7A. This is not the right answer.
B He and Ne These elements have similar properties becase they are in the same group (8A).
C Al and Si These elements do not have similar properties because Al is in group 3A and Si is in group 4A. This is not the right answer.
D N and S These elements do not have similar properties because N is in group 5A and S is in group 6A. This is not the right 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
d, one atom of oxygen and two atoms of hydrogen
Answer:
A water molecule consists of three atoms; an oxygen atom and two hydrogen atoms, which are bond together like little magnets. The atoms consist of matter that has a nucleus in the centre. one mole of water contains 6.02 x 1023 MOLECULES of water But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 1024 atoms in a mole of water.Feb 12, 2003
Explanation:
Why did you post this again? Because you're lazy and wanted people to not see my post? Once again, ONE QUESTION AT A TIME. We're here to help you with a tough question or work you through it, not do all your homework.
