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Trava [24]
4 years ago
8

Which electron configuration represents an

Chemistry
1 answer:
Natasha_Volkova [10]4 years ago
5 0
The answer is (3) 2-8-8-1
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A 0.366 mol sample of pcl5(g) is injected into an empty 4.45 l reaction vessel held at 250 °c. calculate the concentrations of p
Maru [420]
Chemical reaction: PCl₅ → PCl₃ + Cl₂.
n(PCl₅) = 0,366 mol.
V(PCl₅) = 4,45 L.
c(PCl₅) = n(PCl₅) ÷ V(PCl₅).
c(PCl₅) = 0,366 mol ÷ 4,45 L.
c(PCl₅) = 0,082 mol/L.
Kc = 1,80.
[PCl₃] = [Cl₂] = x.
Kc = [PCl₃] · [Cl₂] ÷ [PCl₅].
1,80 = x² ÷ (0,082 mol/L - x).
Solve quadratic eqaution: x = [PCl₃] = 0,078 mol/L.
[PCl₅] = 0,082 mol/L - 0,078 mol/L.
[PCl₅] = 0,004 mol/L.
6 0
3 years ago
In the titration of 50.0 mL of HCl of unknown concentration, the phenolphthalein indicator present in the colorless solution tur
KIM [24]

Answer:

The molarity of HCl is 0.138 M

Explanation:

The titration reaction is as follows:

2HCl + Ca(OH)₂ → CaCl₂ + 2H₂O

When no more HCl is left, the small excess of Ca(OH)₂ added will cause the pH to rise and the indicator will turn. At this point, the number of moles of Ca(OH)₂ added will be the same as half the number of moles of HCl since 1 mol Ca(OH)₂ reacts with 2 moles HCl. Then:

At the endpoint:

moles Ca(OH)₂  = moles HCl / 2

Knowing the number of moles of Ca(OH)₂ added, we can calculate the number of moles of the acid:

mol Ca(OH)₂ = Volume added * concentration of Ca(OH)₂

mol Ca(OH)₂ = 0.0265 l * 0.130 mol/l = 3.45 x 10⁻³ mol Ca(OH)₂

The number of moles of HCl will be:

mol HCl = 2 * 3.45 x 10⁻³ mol = 6.89 x 10⁻³ mol HCl

This number of moles was present in 50.0 ml, then, in 1000 ml:

mol of HCl in 1000 ml = 6.89 x 10⁻³ mol HCl * (1000ml / 50ml) = 0.138 mol

Then:

Molarity HCl = 0.138 M

7 0
4 years ago
Balance the single replacement chemical reaction.
OLEGan [10]

Answer:

Option c. 2Kl + Cl2 —> 2KCl + l2

Explanation:

A balanced equation must have the same number of atoms on the reactants side and the products side. This do the fact of the postulation by the mass conservation principle that says: Atoms can neither be broken nor destroyed but can be arranged. The atoms on the left side for each element are equal. Thus, C presents a balanced equation.

3 0
4 years ago
Identify What are the charges on ions of Group 1A,<br> Group 3A (aluminum), and Group 5A?
dalvyx [7]

Explanation:

 Group 1A         +1

 Group 3A         +3 or +1

 Group 5A         +5 or +3

The charges on an ion signifies the number of electrons that has been lost, gained or shared by an atom. These electrons are called valence electrons occupying the outermost shell of an atom.

 Group 1A element will readily be willing to lose an electron giving them a charge of +1

  Group 3A can lose either 1 or 3 electrons giving a charge of +3 or +1

  Group 5A can lose either 5 or 3 electrons giving a charge of +5 or +3

The number of lost electron confers the stability on the configuration.

Learn more:

Charges brainly.com/question/8849218

#learnwithBrainly

4 0
3 years ago
When we put energy into a substance, what
Gwar [14]

Answer:

i dunno if this helps :(

Explanation:

Heat is energy transferred between substances or systems due to a temperature difference between them, according to Energy Education. As a form of energy, heat is conserved, i.e., it cannot be created or destroyed. It can, however, be transferred from one place to another.

8 0
3 years ago
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