1. Subscript is below
2. Coefficient large 2 indicates the number of moles
3. Atoms
1/2 O2 + H2 —> H2O
It’s the atoms that balance on each side
Notes that 1/2 is the coefficient and 2 is the subscript in H2 and H2O
We are given that the concentration of NaOH is 0.0003 M and are asked to calculate the pH
We know that NaOH dissociates by the following reaction:
NaOH → Na⁺ + OH⁻
Which means that one mole of NaOH produces one mole of OH⁻ ion, which is what we care about since the pH is affected only by the concentration of H⁺ and OH⁻ ions
Now that we know that one mole of NaOH produces one mole of OH⁻, 0.0003M NaOH will produce 0.0003M OH⁻
Concentration of OH⁻ (also written as [OH⁻]) = 3 * 10⁻⁴
<u>pOH of the solution:</u>
pOH = -log[OH⁻] = -log(3 * 10⁻⁴)
pOH = -0.477 + 4
pOH = 3.523
<u>pH of the solution:</u>
We know that the sum of pH and pOH of a solution is 14
pH + pOH = 14
pH + 3.523 = 14 [subtracting 3.523 from both sides]
pH = 10.477
The <u>Mole</u> is the SI unit that expresses the amount of substance.
Mole is defined as - The mole is the amount of substance containing the same number of entities as there are in the 12 grams of Carbon - 12.
Mole is denoted by using symbol mol.
Mole = 6.022 x 10²³ elementary entities.
These number of elementary entities in 1 mole is equal to or called as an Avogadro's number. Mole is equal to 6.022 x 10²³ because this number of entity is same as in exactly 12 g of carbon-12.
It is a very important SI unit of measured which is used by the chemists. Moles are used in measuring in small or tiny things such as atoms, molecules and the other tiny particles.
To learn more about the mole concept,
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Explanation:
A compound is defined as follows.
- Compounds are pure substance.
- The atoms bonded in a compound are in specific proportion.
- A compound is formed by chemical combination.
- For a compound, melting point and boiling point is defined.
A mixture is defined as follows.
- Mixtures are impure substance.
- The bonded atoms in a mixture are in any proportion.
- A mixture is formed by physical combination.
- For a mixture, melting point and boiling point is not defined.
On changing the amount of one substance will affect the formation of compound as a compound requires atoms to be bonded in a specific proportion. Whereas changing the amount of one substance will not affect the formation of mixtures as atoms can be bonded in any proportion in a mixture.
The electronic configuration of n - 3 ion is [He] 2s2 2p3.