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3 years ago

Which of the following elements is the least reactive metal? Sodium, Rubidium, Chlorine, and Magnesium.

1 answer:

6 0

First off chlorine is not a metal so you can ignore that one.

Sodium and Rubidium are in group 1 of the periodic table and Magnesium is in group 2.

Group one metals are more reactive than group two because it is harder for the group two metals to lose their 2 valence (outer most) electrons.

As you go down group 1 there is an increase in the reactivity this is because as you go down there is an increase in the atomic radius which leads to more shielding. This weakens the electrostatic forces of attraction making it easier to lose the outermost electrons, therefore they are more reactive.

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Predict the sign of ΔSo for the following reaction:

Sergio [31]

Answer: Option (a) is the correct answer.

Explanation:

Entropy means the degree of randomness present within the molecules of an object.

When a substance is present in a solid state then its molecules are held together because of strong intermolecular forces of attraction.

As a result, molecules are not able to move freely and therefore, there will be no randomness.

But when a substance changes into liquid state then its molecules mover further apart from each other due to gain in kinetic energy. Hence, randomness increases.

On the other hand, when a substance moves from liquid to gaseous state then its molecules gain more kinetic energy due to which there will be high degree of randomness.

Therefore, as the products in the given reaction are present in liquid and gaseous state. So, this means that there has been an increase in entropy.

A decrease in entropy is represented by negative sign and an increase in entropy is represented by a positive sign.

Thus, we can conclude that the sign of $\Delta S_{o}$ for the given reaction is $\Delta S_{o}$ > 0.

8 0

3 years ago

Calculate the percent ionization of nitrous acid in a solution that is 0.311 M in nitrous acid (HNO2) and 0.189 M in potassium n

Alla [95]

HNO2 =====> H+ + NO2-
Initial concentration = 0.311
C = -x,x,x 
E = 0.311-x,x,x

KNO2 ====>K+ + NO2-
Initial concentration = 0.189 
C= -0.189,0.189,0.189 
E = 0,0.189,0.189

6 0

3 years ago

Given 25.43 g of O2 gas, how many liters of gas will you have at STP? Answer value

Paraphin [41]

Given :

Mass of O₂, m = 25.43 g.

To Find :

How many liters of gas will you have at STP.

Solution :

Molecular mass of O₂, M.M = 2 × 16 gram/mole

M.M = 32 gram/mole

Number of moles is given by :

n = m/M.M

n = 25.43/32 mole

n = 0.79 mole

Hence, this is the required solution.

4 0

3 years ago

Which of the following describes the characteristics of a plasma?

Scorpion4ik [409]

There are essentially 5 states of matter-

1) Solid

2) Liquid

3) Gas

4) Plasma

5) Bose-Einstein Condensate

Plasma comprises of positive and negatively charged particles that are formed in extremely high temperature conditions. A characteristic of plasma is that it is not dense enough. The ions tend to be far apart, which makes them to spread out and imparts compressibility.

Ans B)

7 0

3 years ago

Which element has properties of both metals and nonmetals?

PilotLPTM [1.2K]

Metalloids have the properties of metals and nonmetals.

8 0

3 years ago

Which of the following elements is the least reactive metal? Sodium, Rubidium, Chlorine, and Magnesium.​

Which of the following elements is the least reactive metal? Sodium, Rubidium, Chlorine, and Magnesium.