Answer:
2.30 × 10⁻⁶ M
Explanation:
Step 1: Given data
Concentration of Mg²⁺ ([Mg²⁺]): 0.039 M
Solubility product constant of Mg(OH)₂ (Ksp): 2.06 × 10⁻¹³
Step 2: Write the reaction for the solution of Mg(OH)₂
Mg(OH)₂(s) ⇄ Mg²⁺(aq) + 2 OH⁻(aq)
Step 3: Calculate the minimum [OH⁻] required to trigger the precipitation of Mg²⁺ as Mg(OH)₂
We will use the following expression.
Ksp = 2.06 × 10⁻¹³ = [Mg²⁺] × [OH⁻]²
[OH⁻] = 2.30 × 10⁻⁶ M
28) All elements are made of atoms
29)Protons and Neutrons
-Electrons make up the outside of the Nucleus
<u>Answer:</u> The chemical equation is written below.
<u>Explanation:</u>
Every balanced chemical equation follows law of conservation of mass.
This law states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form. This also means that total number of individual atoms on reactant side must be equal to the total number of individual atoms on the product side.
The chemical equation for the reaction of elemental boron and oxygen gas follows:

By Stoichiometry of the reaction:
4 moles of elemental boron reacts with 3 moles of oxygen gas to produce 2 moles of diboron trioxide.
The chemical equation for the reaction of diboron trioxide and water follows:

By Stoichiometry of the reaction:
1 mole of diboron trixoide reacts with 3 moles of water to produce 2 moles of boric acid.
Hence, the chemical equations are written above.
Answer:
1) The volume occupied by an atom is composed of mainly empty space
2) Atoms have a very small, relatively dense, central nucleus that is positively charged
3) The region around the nucleus of an atom are orbited by negatively charged electrons in a the same fashion planets orbit around the Sun.
Explanation:
The selection of gold for the gold foil experiment was due to its ability to be rolled into extremely thin sheets such that it was expected for alpha particle to perforate or pass through the foil.