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1 year ago

Ii) The valency of which the element is zero.a) lead. b) bromine c) helium. d) nitrogen

Chemistry

2 answers:

VashaNatasha [74]1 year ago

7 0

Answer:

Helium

Explanation:

As the elements have the maximum number of electrons in their valence shells (thereby achieving stable duplet and octet configurations), they do not have any tendency to combine with other elements.

stira [4]1 year ago

6 0

Answer:

Helium, Neon, Radon and Argon have zero valency because they have their outer shell completely filled and are chemically inert gas. Was this answer helpful

Explanation:

hope it will help you

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A diatomic molecule is one that is made of only two different elements ? true or false

Slav-nsk [51]

More specifically two atoms but this is indeed true. The elements do not need to be different but there can only be two atoms. The prefix indicates the quantity of two. Di - means "of two".

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4 years ago

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"Two major varieties of igneous rock are _______ and ________. What is the difference between these two types of igneous rock?"

grandymaker [24]

Answer:

Intrusive and Extrusive igneous rocks.

Explanation:

Igneous rocks are defined as those rocks that are formed when magma undergoes the process of crystallization and solidification at or below the earth's surface. For example, Granite, Rhyolite, Gabbro and Diorite.

The igneous rocks are of two different types, namely-

Intrusive igneous rocks- This type of igneous rocks are formed when the magma crystallizes below or within the earth's crust. For example, Granite.

Extrusive igneous rocks- This type of igneous rocks are formed when the magma crystallizes and solidifies at the surface of the earth. For example, Basalt.

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3 years ago

You draw back on the piston of a pump and the volume of air in the pump doubles. Which of the following happens?

ohaa [14]

Answer: The correct answer is Option C.

Explanation:

We are given a piston of a pump, which means that there is no loss of the air. and there is a change in pressure and volume but temperature of the system remains constant.

As, the pressure of the system increases, there will be more number of particles. So, the number of collisions per unit area will increase.

$\text{Number of collisions}\propto \text{Pressure}$

But in the question, volume gets doubled. So, the pressure will be determined by using Boyle's Law:

$P\propto \frac{1}{V}$

$V_2\rightarrow 2V_1$

where, $V_1\text{ and }V_2$ are the initial and final volume respectively.

Putting the change in volume in above equation, we get:

$P_2=\frac{1}{2V_1}\\\\P_2=\frac{1}{2}P_1$

where, $P_1\text{ and }P_2$ are the initial and final pressure respectively.

As, the pressure is reduced to half of the initial pressure. So, the number of collisions per unit area will also be reduced to one-half.

Hence, the correct answer is Option C.

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3 years ago

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From the following reaction and data, find (a) S o of SOCl2 (b) T at which the reaction becomes nonspontaneous SO3(g) + SCl2(l)

disa [49]

Answer:

618 J/Kmol

T > 1.36 x 10³ K

Explanation:

The balanced reaction of interest is:

SO₃ (g) + SCl₂ (l) ⇒ SOCl₂ (l) + SO₂ (g)

with the data:

ΔHºf (kJ/mol) -396 -50.0 -245.6 -296.8

Sº(J/mol·K) 256.7 184 ? -248.1

ΔGº= -75.2 kJ

We know, we can find the standard change inGibb´s free energy from the equation:

ΔGºrxn = ΔHºrxn - TΔSºrxn

So we can calculate ΔHºrxn = ∑ ΔHºf prod - ΔHºreact, and substitute into this equation to solve Sº SOCl₂.

ΔHºrxn = ( -245.6 + (-296.8) ) - ( -396 - 50) kJ = - 96.4 kJ

Similarly for ΔSºrxn

ΔSºrxn = (-0.248.1 +Sº SOCl₂) - (0.256.7 +0.184) kJ/K

= -0.689 kJ /K -+ Sº SOCl₂

Plugging the values for the expression for ΔGºrxn:

-75.2 kJ = -96.4 kJ - 298 K x ( -0.689 kJ /K + Sº SCl₂ )

-75.2 kJ = -96.4 kJ + 205.3 Kj - 298 Sº SCl₂

-184 kJ = -298 K x Sº SCl₂

0.618 kJ/molK = Sº SCl₂

= 0.618 kJ/K x 1000 J = 618 J/Kmol

For the second part we will still be using the Gibb´s free energy change equation as above , but now we will solve for T when the reaction becomes non-spontaneous.

For the reaction to become non-spontaneous ΔGº is positive, and this happens when the term TΔSº becomes greater tha ΔHº:

ΔGºrxn = ΔHºrxn - TΔSºrxn

0 = ΔHºrxn - TΔSºrxn ⇒ TΔSºrxn = ΔHºrxn

T= ΔHºrxn / ΔSºrxn

ΔSºrxn = -0.689 J/Kmol + 0.618 J/Kmol = -0.0710 kJ/Kmol

( using the value the value just calculated from above )

T = - 96.4 kJ / -0.071 kJ/K = 1.36 x 10³ K

For temperatures greater than 1.36 x 10³ K the reaction becomes non-spontaneous.

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4 years ago

What is a wave in science terms?

Vlad1618 [11]

Answer: Waves involve the transport of energy without the transport of matter. In conclusion, a wave can be described as a disturbance that travels through a medium, transporting energy from one location (its source) to another location without transporting matter.

Explanation:

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3 years ago

Ii) The valency of which the element is zero.a) lead. b) bromine c) helium. d) nitrogen​

Ii) The valency of which the element is zero.a) lead. b) bromine c) helium. d) nitrogen