<span>PbO
Let's look at each of the 4 compounds and see what's needed.
PbO.
* Oxygen has a valance shell that's missing 2 electrons and wants to get those 2 elections. Lead donates them, so you have a Lead (II) ions. This is a correct choice.
PbCl4
* Chlorine wants to grab 1 electron to fill it's valance shell and Lead donates that election. However, there's 4 chlorine atoms and every one of them wants and electron, and lead is donating all 4 of the desired electrons making the Lead (IV) ion. So this is a bad choice.
Pb2O
* Oxygen still wants 2 electrons and gets them from the lead. But there's 2 lead atoms and each of them donates 1 election making for 2 Lead(I) ions. So this too is a bad choice.
Pb2S
* Sulfur is in the same column of the periodic table as oxygen and if this compound were to exist would have similar properties as Pb2O and would have Lead(I) ions. So this is a bad choice.</span>
Evaporation occurs when water molecules on the surface gain enough energy to enter the atmosphere. However, stronger intermolecular forces between water molecules cause them to be strongly attracted to each other and to tend to stay in the liquid phase. When the temperature is raised (when heat is applied), more molecules gain the energy needed to escape these intermolecular forces and go into the vapor phase.
Therefore the best answer is D.
Answer:
D) 5.15
Explanation:
Step 1: Write the equation for the dissociation of HCN
HCN(aq) ⇄ H⁺(aq) + CN⁻(aq)
Step 2: Calculate [H⁺] at equilibrium
The percent of ionization (α%) is equal to the concentration of one ion at the equilibrium divided by the initial concentration of the acid times 100%.
α% = [H⁺]eq / [HCN]₀ × 100%
[H⁺]eq = α%/100% × [HCN]₀
[H⁺]eq = 0.0070%/100% × 0.10 M
[H⁺]eq = 7.0 × 10⁻⁶ M
Step 3: Calculate the pH
pH = -log [H⁺] = -log 7.0 × 10⁻⁶ = 5.15
Answer:
Germanium
Explanation:
The element Germanium is one with a relative molecular mass of 72. This corresponds to the mass number of this element.
Relative molecular mass of an element is the mass of a formula unit to that of a carbon-12 atom.
The chemical symbol of Germanium is Ge. It is a lustrous and hard metalloid belonging to the carbon group.
It was discovered by Clemens Alexander Winkler.
Answer is: this is an example of an Arrhenius acid.
An Arrhenius acid is a
substance that dissociates in water to form hydrogen ions or protons (H⁺).
For example hydrochloric acid: HCl(aq) → H⁺(aq) + Cl⁻(aq).
An Arrhenius base is a
substance that dissociates in water to form hydroxide ions (OH⁻<span>).
In this example lithium hydroxide is an Arrhenius base:</span>
LiOH(aq) → Li⁺(aq) + OH⁻(aq).
