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tensa zangetsu [6.8K]

2 years ago

12

What is the Nobel gas notation for selenium

1 answer:

seraphim [82]2 years ago

5 0

Answer:

Se =[Ar] 3d¹⁰ 4s² 4p⁴

Explanation:

The noble gas notation is used for the shortest electronic configuration of other periodic table elements.

For example:

The atomic number of Argon is 18, and its electronic configuration is,

Ar₁₈ = 1s² 2s² 2p⁶ 3s² 3p⁶

The atomic number of selenium is 34, its electronic configuration is,

Se₃₄ = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁴

By using the noble gas notation, electronic configuration of selenium can be written is shortest form.

Se =[Ar] 3d¹⁰ 4s² 4p⁴

This electronic configuration is also called abbreviated electronic configuration.

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4 0

3 years ago

If 185 mg of acetaminophen were obtained from a tablet containing 350 mg of acetamino- phen, what would be the weight percentage

Alex73 [517]

Percentage recovery gives us an idea of the amount of pure substance recovered after the chemical reaction. Percentage recovery can be more than 100 % or less than 100 %. Usually, in any experiment performed the weight percentage recovery will be less than 100. Percent recovery values greater than 100 show that the recovered compound is contaminated.

Amount of acetaminophen initially taken = 350 mg

Amount of acetaminophen obtained after recovery =185 mg

$Weight percentage recovery =\frac{mass recovered}{mass originally taken}*100$

= $\frac{185 mg}{350 mg}*100$

= 52.9%

8 0

2 years ago

How many half-lives are required for the concentration of reactant to decrease to 1.56% of its original value?4247.56.56

neonofarm [45]

Answer:

6 half-lives are required for the concentration of reactant to decrease to 1.56% of its original value.

Explanation:

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given:

Concentration is decreased to 1.56 % which means that 0.0156 of $[A_0]$ is decomposed. So,

$\frac {[A_t]}{[A_0]}$ = 0.0156

Thus,

$\frac {[A_t]}{[A_0]}=e^{-k\times t}$

$0.0156=e^{-k\times t}$

kt = 4.1604

The expression for the half life is:-

Half life = 15.0 hours

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$\frac{4.1604}{t}=\frac {ln\ 2}{t_{1/2}}$

$t = 6\times t_{1/2}$

<u>6 half-lives are required for the concentration of reactant to decrease to 1.56% of its original value.</u>

6 0

3 years ago

A particular voltaic cell operates with the reaction: Zn(s)+Cl2(g)--->Zn^2+(aq)+2Cl^-(aq) giving a cell potential of .853 V.

nadya68 [22]

Answer:

The amount of energy liberated will be 49.38 J.

Explanation:

The amount of energy liberated (gibbs free energy) can be calculated using the following equation:

ΔG° = -nFε

n: amount of moles of electrons transfered

F: Faraday's constant

ε: cell potential

20.0 g of Zn is equal to 0.30 mol.

Two electrons are transfered during the reaction.

Therefore, n = 2x0.30 ∴ n = 0.60

ΔG° = - 0.60 x 96.485 x 0.853

ΔG° = 49.38 J

3 0

3 years ago

If the valency of oxygen is 2, derive the valencies of the other elements present in the following oxides. Na2O, ZnO , Al2O3 , M

11Alexandr11 [23.1K]

Answer:

1)Na2O

let the valency of Na is x

2(x)+(2)=0

2x+2=0

2x=-2

x=-1

2)ZnO

let the valency of Zn is x

x+2=0

x=-2

3)Al2O3

let the valency of Al is x

2(x)+3(2)=0

2x+6=0

2x=-6

x=-3

4)MgO

let the valency of Mg is x

x+2=0

x=-2

7 0

3 years ago

Read 2 more answers