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2 years ago

Name an element in the fifth period (row) of the periodic table with a complete outer shell.

Chemistry

2 answers:

lorasvet [3.4K]2 years ago

4 0

Answer: The element in fifth period of the periodic table having complete outer shell is Xenon.

Explanation:

Elements are distributed in 7 periods and 18 groups. Groups are the vertical columns and periods are the horizontal rows.

Element having complete outer shells are present in Group 18 of the periodic table. These elements are known as noble gases.

Element present in Period 5 and Group 18 of the periodic table is Xenon.

The atomic number of Xenon is 54.

Hence, the element in fifth period of the periodic table having complete outer shell is Xenon.

katen-ka-za [31]2 years ago

3 0

I suppose it could be Xenon, but I'm not pretty sure about this.

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How many moles of electrons must be transferred to plate out 110 g of manganese (MW ~ 55g/mol) from a solution of permanganate (

ololo11 [35]

Answer:

14 mol e⁻

Explanation:

Step 1: Write the balanced half-reaction for the reduction of permanganate to manganese

8 H⁺(aq) + 7 e⁻ + MnO₄⁻(aq) ⇒ Mn(s) + 4 H₂O(l)

Step 2: Calculate the moles corresponding to 110 g of manganese

The molar mass of Mn is 55 g/mol.

110 g × 1 mol/55 g = 2 mol

Step 3: Calculate the number of moles of electrons needed to produce 2 moles of Mn

According to the half-reaction, 7 moles of electrons are required to produce 1 mole of Mn.

2 mol Mn × 7 mol e⁻/1 mol Mn = 14 mol e⁻

8 0

3 years ago

Water has a boiling point of 100.0°C and a Kb of 0.512°C/m. What is the boiling

Reil [10]

Answer:

The boiling point of a 8.5 m solution of Mg3(PO4)2 in water is 394.91 K.

Explanation:

The formula for molal boiling Point elevation is :

$\Delta T_{b} = iK_{b}m$

$\Delta T_{b}$ = elevation in boiling Point

$K_{b}$ = Boiling point constant( ebullioscopic constant)

m = molality of the solution

i = Van't Hoff Factor

Van't Hoff Factor = It takes into accounts,The abnormal values of Temperature change due to association and dissociation .

In solution Mg3(PO4)2 dissociates as follow :

$Mg_{3}(PO_{4})_{2}\rightarrow 3Mg^{2+} + 2 PO_{4}^{3-}$

Total ions after dissociation in solution :

= 3 ions of Mg + 2 ions of phosphate

Total ions = 5

i = Van't Hoff Factor = 5

m = 8.5 m

$K_{b}$ = 0.512 °C/m

Insert the values and calculate temperature change:

$\Delta T_{b} = iK_{b}m$

$\Delta T_{b} = 5\times 0.512\times 8.5$

$\Delta T_{b} = 21.76 K$

Boiling point of pure water = 100°C = 273.15 +100 = 373.15 K

$\Delta T_{b} = T_{b} - T_{b}_{pure}$

$T_{b}_{pure}$ = 373.15 K[/tex]

21.76 = T - 373.15

T = 373.15 + 21.76

T =394.91 K

8 0

3 years ago

Identify which sets of Quantum Numbers are valid for an electron. Each set is ordered (n,ℓ,mℓ,ms).

skad [1K]

3,2,0,1/2

1,0,0,1/2

3,2,2,1/2

4,2,1,1/2

2,1,-1,-1/2

THEY ARE VALID

3 0

3 years ago

7. Calculate the amount of energy required heat 100.g to H2O(s) changes to H2O(l) at 0°C

Brrunno [24]

Answer:

33300J

Explanation:

Given parameters:

Mass of ice = 100g

Unknown:

Amount of energy = ?

Solution:

This is a phase change process from solid to liquid. In this case, the latent heat of melting of ice is 3.33 x 10⁵ J/kg.

So;

H = mL

m is the mass

L is the latent heat of melting ice

Now, insert the parameters and solve;

H = mL

mass from gram to kilogram;

100g gives 0.1kg

H = 0.1 x 3.33 x 10⁵ = 33300J

8 0

2 years ago

When maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas write the balanved equati

babunello [35]

Answer: When maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas then balanced equation is $MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$ .

Explanation:

The word equation is given as maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas.

Now, in terms of chemical formulae this reaction equation will be as follows.

$MnO_{2} + HCl \rightarrow H_{2}O + MnCl_{2} + Cl_{2}$

Here, number of atoms on reactant side are as follows.

Mn = 1
O = 2
H = 1
Cl = 1

Number of atoms on product side are as follows.

Mn = 1
O = 1
H = 2
Cl = 4

To balance this equation, multiply HCl by 4 on reactant side and multiply $H_{2}O$ by 2 on product side. Therefore, the equation can be rewritten as follows.

$MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$

Hence, number of atoms on reactant side are as follows.

Mn = 1
O = 2
H = 4
Cl = 4

Number of atoms on product side are as follows.

Mn = 1
O = 2
H = 4
Cl = 4

Since, this equation contains same number of atoms on both reactant and product side. Therefore, this equation is now balanced equation.

Thus, we can conclude that when maganese dioxide is added to hydrogen chloride you get water maganese dichloride and chlorine gas then balanced equation is $MnO_{2} + 4HCl \rightarrow 2H_{2}O + MnCl_{2} + Cl_{2}$ .

6 0

3 years ago