Answer:
0.6 moles of Fe
Explanation:
Given data:
Number of atoms of Fe = 3.612×10²³
Number of moles = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
From atoms to mole:
3.612×10²³ atoms of Fe × 1 mole / 6.022 × 10²³ atoms
0.6 moles of Fe
Answer:
A. To focus on only those ions that form the precipitate
Explanation:
Net ionic equations cancel out the ions that appear on both sides of the reaction because they essentially don't participate in the reaction. This is very useful when dealing with redox reactions because are complicated enough without spectator ions being in the way, so they help focus on those ions that actually form the precipitate.
Key Terms
- Spectator Ions: an ion that does not take part in the chemical reaction.
- Net ionic equations: a equation where ions that appear on both sides are canceled out.
- Redox reaction: an oxidation-reduction reaction.
Answer:
HCI
Explanation:
The solution with the lowest pH is HCI with a pH value of 1. It is understood that it is more acidic because it is a strong acid.
First, we need to get the value of Ka:
when Ka = Kw / Kb
we have Kb = 1.8 x 10^-5
and Kw = 3.99 x 10^-16 so, by substitution:
Ka = (3.99 x 10^-16) / (1.8 x 10^-5) = 2.2 x 10^-11
by using the ICE table :
NH4+ + H2O →NH3 + H+
intial 0.013 0 0
change -X +X +X
Equ (0.013-X) X X
when Ka = [NH3][H+] / [NH4+]
by substitution:
2.2 x 10^-11 = X^2 / (0.013 - X) by solving this equation for X
∴X = 5.35 x 10^-7
∴[H+] = X = 5.35 x 10^-7
∴PH = - ㏒[H+]
= -㏒(5.35 x 10^-7)
= 6.27
