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2 years ago

What is the electron shielding effect? What is the trend for it? How and why does it happen?

Chemistry

1 answer:

andriy [413]2 years ago

6 0

Answer:

See explanation

Explanation:

In an atom, the inner electrons may shield the outer electrons from the attractive force of the nucleus. We, refer to this phenomenon as the <u><em>shielding effect</em></u>, It is defined as a decrease in the magnitude of attraction between an electron and the nucleus of an atom having more than one electron shell (energy level).

Shielding effect increases down the group due to addition of more shells but decreases across the period due to the increase in the size of the nuclear charge.

As the magnitude of shielding increases down the group, ionization of electrons becomes easier and the first ionization energies of elements decreases as we move down the group. Since shielding effect decreases across the period, the first ionization energies of elements increases across the period.

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The Tacoma narrows bridge collapsed due to?

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Explanation: aeroflastic flutter

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3 years ago

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Given that ΔH = −571.6 kJ/mol for the reaction 2 H2(g) + O2(g) → 2 H2O(l), calculate ΔH for these reactions. (a) 2 H2O(l) → 2 H2

pashok25 [27]

Answer : The value of $\Delta H$ for the reaction is +571.6 kJ/mole.

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction is,

$2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$ $\Delta H_1=-571.6kJ/mole$

Now we have to determine the value of $\Delta H$ for the following reaction i.e,

$2H_2O(l)\rightarrow 2H_2(g)+O_2(g)$ $\Delta H_2=?$

According to the Hess’s law, if we reverse the reaction then the sign of $\Delta H$ change.

So, the value $\Delta H_2$ for the reaction will be:

$\Delta H_2=-(-571.6kJ/mole)$

$\Delta H_2=+571.6kJ/mole$

Hence, the value of $\Delta H$ for the reaction is +571.6 kJ/mole.

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2 years ago

How many atoms are ln 6.31 moI of sodium sulfate

Art [367]

896.27
One mole of sodium sulfate is 143.04, so just multiply that times 6.31.
I may be wrong call me out if I am

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2 years ago

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What does unsaturated zone mean?

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The unsaturated zone is the portion of the subsurface above the groundwater table. The soil and rock in this zone contains air as well as water in its pores. ... Unlike the aquifers of the saturated zone below, the unsaturated zone is not a source of readily available water for human consumption

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3 years ago

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On a recent trip to the Fort Worth Zoo, Trevor's parents bought him a helium-filled balloon. At the beginning of the day, the sk

timurjin [86]

Answer:

1. The new volume is 14L

2. The volume decreased

Explanation:

Step 1:

Data obtained from the question.

Initial Volume (V1) = 14.2 L

Initial pressure (P1) = 102.5 kPa

Initial temperature (T1) = 33°C

Final pressure (P2) = 100.9 kPa

Final temperature (T2) = 24°C.

Final volume (V2) =?

Step 2:

Conversion of celsius temperature to Kelvin temperature. This is illustrated below:

K = °C + 273

T1 = 33°C = 33°C + 273 = 306K

T2 = 24°C = 24°C + 273 = 297K

Step 3:

Determination of the new volume.

Applying the general gas equation P1V1/T1 = P2V2/T2, the new volume can be obtain as follow:

P1V1/T1 = P2V2/T2

102.5 x 14.2/306 = 100.9 x V2/297

Cross multiply to express in linear form as shown below:

306 x 100.9 x V2 = 102.5 x14.2 x297

Divide both side by 306 x 100.9

V2 = (102.5x14.2x297)/(306 x 100.9)

V2 = 14 L

The new volume is 14 L.

Step 4:

Determination of the change in volume. This is illustrated below

Final volume (V2) = 14 L

Initial volume (V1) = 14.2 L

Change in volume (ΔV) =?

Change in volume (ΔV) = Final volume (V2) - Initial volume (V1)

ΔV = V2 - V1

ΔV = 14 - 14.2

ΔV = - 0.2L

Since the change in volume is negative, it means there is a decrease in the volume.

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