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Stella [2.4K]
3 years ago
8

Which of the following elements matches the criteria below?

Chemistry
1 answer:
Tems11 [23]3 years ago
4 0

Answer:

The answer to your question is below

Explanation:

1. Found in period 2. All the elements in the list are found in period 2.

a. F   This option is correct

b. Be  Beryllium is located in period two.

c. O  also oxygen is found in period 2.

d. C Carbon is found in period 2.

2.- Can gain lose 4 electrons to become its nearest stable noble gas. Only Carbon.

a. F    This option is wrong, F becomes stable when it gains 1 electron.

b. Be  Beryllium becomes stable when it loses 2 electrons.

c. O  Become stable when it gains 2 electrons.

<u>d. C </u><u>Become stable when it gains or loses 4 electrons.</u>

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A reaction has a forward rate constant of 2.3 × 106 s-1 and an equilibrium constant of 4.0 × 108. what is the rate constant for
avanturin [10]
Answer is: 5,75·10⁻¹.
Kf = 2,3·10⁶ 1/s.
K = 4,0·10⁸ 1/s.
Kr = ?
Kf - <span>forward rate constant.
K - </span><span>equilibrium constant.
Kr - </span><span>reverse rate constant.
</span>Since both Kf and Kr are constants at a given temperature, their ratio is also a constant that is equal to the equilibrium constant K.<span>
K = Kf/Kr.
Kr = Kf/K = </span>2,3·10⁶ 1/s ÷ 4,0·10⁸ 1/s = 5,75·10⁻¹.

5 0
3 years ago
When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II)
lesya692 [45]

Answer: The mass of lead deposited on the cathode of the battery is 1.523 g.

Explanation:

Given: Current = 62.0 A

Time = 23.0 sec

Formula used to calculate charge is as follows.

Q = I \times t

where,

Q = charge

I = current

t = time

Substitute the values into above formula as follows.

Q = I \times t\\= 62.0 A \times 23.0 sec\\= 1426 C

It is known that 1 mole of a substance tends to deposit a charge of 96500 C. Therefore, number of moles obtained by 1426 C of charge is as follows.

Moles = \frac{1426 C}{96500 C/mol}\\= 0.0147 mol

The oxidation state of Pb in PbSO_{4} is 2. So, moles deposited by Pb is as follows.

Moles of Pb = \frac{0.0147}{2}\\= 0.00735 mol

It is known that molar mass of lead (Pb) is 207.2 g/mol. Now, mass of lead is calculated as follows.

No. of moles = \frac{mass}{molar mass}\\ 0.00735 = \frac{mass}{207.2 g/mol}\\mass = 1.523 g

Thus, we can conclude that the mass of lead deposited on the cathode of the battery is 1.523 g.

3 0
2 years ago
Idenify each statement below as either oxidation or reduction.
Alenkasestr [34]

Answer:

1 = oxidation

2 = reduction

Explanation:

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

2I- ----> I₂+ 2e⁻

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

F + e⁻ ----> F⁻

Consider the following reactions.

4KI + 2CuCl₂  →   2CuI  + I₂  + 4KCl

the oxidation state of copper is changed from +2 to +1 so copper get reduced.

CO + H₂O   →  CO₂ + H₂

the oxidation state of carbon is +2 on reactant  side and on product side it becomes  +4 so carbon get oxidized.

Na₂CO₃ + H₃PO₄  →  Na₂HPO₄ + CO₂ + H₂O

The oxidation state of carbon on reactant side is +4. while on product side is  also +4 so it neither oxidized nor reduced.

H₂S + 2NaOH → Na₂S + 2H₂O

The oxidation sate of sulfur is -2 on reactant side and in product side it is also -2 so it neither oxidized nor reduced.

4 0
2 years ago
Which is heavier einsteinium (Es) or europium (Eu)
Maksim231197 [3]

Answer:

Einsteinium is heavier

Explanation:

Atomic weight is what we are referring to when figuring out how heavy an element is and is measured in amu (atomic mass units)

(This is also the same as the molar mass how heavy 6.022 x 10^23 atoms of a substance or element is which is measured in grams)

The atomic weight of an element can be found on a periodic table.

Europium has an atomic mass of approximately 152 amu (atomic mass units)

Einsteinium has an atomic mass of approximately 252 amu.

Einsteinium has a higher atomic weight so it's heavier.

There's another easier way of going about it where you don't even have to think about the actual number and basically just look at the element's atomic number and position on the periodic table.

Eu is 63

Es is 99

As the atomic number increases on the periodic table this means it's number of protons is greater.

Protons lie in the nucleus which has most of the atom's weight so the more protons the heavier it is.

Einsteinium has a higher atomic number meaning it has more protons so we can assume it's the heavier one.

Hope this helps!

3 0
3 years ago
Help please chemistry question
Gemiola [76]

Answer:

D. K_{a} = \frac{[\text{H}^{+}][\text{NO}_{2}^{-}]}{[\text{HNO}_{2}]}

Explanation:

The general form of an equilibrium constant expression is

K = \frac{[\text{Products}]}{[\text{Reactants}]}

In the equilibrium

HNO₂ ⇌ H⁺ + NO₂⁻

The products are H⁺ and NO₂⁻, and the reactant is HNO₂.

∴ K_{a} = \frac{[\text{H}^{+}][\text{NO}_{2}^{-}]}{[\text{HNO}_{2}]}

3 0
3 years ago
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