7 - Neutral because water and salt are neutral substances
pH is a scale used to measure the acidity or
alkalinity of an aqueous solution. It can be used to calculate the amount of
hydronium ions in the solution. It is expressed as the negative logarithm to
the base 10 of the concentration.
<span> </span><span>pH = -log [H+]</span>
<span>pH= -log [4.5 x 10^-3]</span>
pH = 2.35
Answer:
0.18× 10²³ molecules
Explanation:
Given data:
Mass of copper hydroxide = 3.30 g
Number of molecules = ?
Solution:
Number of moles = mass/molar mass
Number of moles = 3.30 g/97.56 g/mol
Number of moles = 0.03 mol
Avogadro number:
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.
1 mole = 6.022 × 10²³ molecules
0.03 mol × 6.022 × 10²³ molecules / 1mol
0.18× 10²³ molecules
Answer:

Explanation:
To answer this question successfully, we need to remember that atoms are neutral species, since the number of protons, the positively charged particles, is equal to the number of electrons, the negatively charged particles. That said, we may firstly find an atom which has 3 electrons (and, as a result, 3 protons, as it should be neutral).
The number of protons is equal to the atomic number of an element. We firstly may have an atom with 3 protons and 3 electrons (atomic number of 3, this is Li).
Similarly, we may take the atomic number of 4, beryllium, and remove 1 electron from it. Upon removing an electron, it would become beryllium cation,
.
We may use the same logic going forward and taking the atomic number of 5. This is boron. In this case, we need to remove 2 electrons to have a total of 3 electrons. Removal of 2 electrons would yield a +2-charged cation:
.
C. Groups 13-16 contain metalloids.
If you look on a periodic table, these usually have a different color.