Which of the following reactions show a decrease in entropy? a. CaO(s) + H2O(l) Ca(OH)2 (s) b. 2H2O (l) 2 H2 (g) + O2 (g) c. H2CO3 (aq) CO2 (g) + H2O (l) d. 2KClO3 (s) 3O2 (g) + 2KCl (s)

Answers

Answer 1

Answer: The correct answer is a. CaO(s) + H2O(l) Ca(OH)2 (s)
Decreasing in entropy means that you have to get a solid from the liquid
therefore : CaO(s) + H2O(l) Ca(OH)2 (s)
This formula will make it absolutely clear
$(g) -\ \textgreater \ (l) -\ \textgreater \ (s) more molecules -\ \textgreater \ less molecules$

Answer 2

Answer:

Answer: The correct answer is Option a.

Explanation:

Entropy is defined as the measurement of randomness in a system.

Entropy increases as we move from solid state to liquid state to gaseous state and it decreases as we move from gaseous state to liquid state to solid state.

From the options above:

Option a: $CaO(s)+H_2O(l)\rightarrow Ca(OH)_2(s)$

Entropy is getting decreased because liquid reactants are changing its state to solid state.

Option b: $2H_2O(l)\rightarrow 2H_2(g)+O_2(g)$

In this reaction, entropy is increasing because the state is changing from liquid to gaseous state.

Option c: $H_2CO_3(aq.)\rightarrow CO_2(g)+H_2O(l)$

In this reaction, entropy is increasing because the state is changing from liquid to gaseous state.

Option d: $2KClO_3(s)\rightarrow 3O_2(g)+2KCl(s)$

In this reaction, entropy is increasing because the state is changing from solid to gaseous state.

Hence, the correct answer is Option a.

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Which metal is more active than H2?
(1) Ag (3) Cu
(2) Au (4) Pb

Answers

Answer is (4) - Pb.

According to the reactivity series of elements

- the elements which are above the hydrogen are more reactive than hydrogen.

- the elements which are below the hydrogen are less reactive than hydrogen.

Among the given choices, only Pb is placed above the hydrogen in the reactivity series and rest are below the hydrogen.

Hence, Pb is more active than hydrogen.

If you mix chlorine lithium and nickel together which two elements would be the most reactive?

Answers

he reactivity of an element increases towards the top and right of the periodic table (until the column of noble gases is reached). Chlorine's outer shell contains 7 electrons that make it very reactive. Helium is a noble gas and is non reactive. Elements found in the middle of the table, like nickel and iron, are reactive, but less reactive than chlorine

Answer:

Helium will be inert. Lithium is the most reactive element, followed by chlorine.

Explanation:

The elements tend to resemble the closest noble gases in terms of their electronic configuration of the last layer, that is, having eight electrons in the last layer to be stable. Then, the reactivity of an element measures the tendency to combine with others to generate the mentioned stability.

Within a period, the groups located on the left of the periodic table are more reactive than groups on the right. This is because it is easier to lose the electron of the last layer possessed by the elements located on the left than more than one electron in the rest of the elements. When we reach a certain group the trend is reversed since it will be easier to gain the missing electrons to resemble the nearest noble gas. Therefore, in a period the reactivity of metals increases the further to the left in the period (less electrons to remove). The reactivity of nonmetals increases as the period progresses since it is the case in which it is easier to acquire electrons to acquire stability, and increases to advance in a period since the less electrons they need to acquire, the more reactants they are.

Within a group, as we descend into it, the electrons of the last layer are farther from the nucleus and, therefore, it will be easier to remove them. In the case of nonmetals, it will be more difficult to take electrons. Then the reactivity of the metals increases when advancing in a group (greater tendency to lose electrons) and the reactivity of the nonmetals increases the higher in the group (greater tendency to take electrons).

Finally, you have noble or inert gases. Its inert name is due to the lack of reactivity with other elements. This is due to its electronic configuration, because its outermost layer or valence layer is always complete, without the need to share, transfer or receive electrons forming bonds. That is, its outer layer is so stable that the element tends not to react with others except in very specific cases.

Taking into account everything mentioned above, it is possible to say that helium is a noble gas, so it will be inert. Lithium is the most reactive element, followed by chlorine.

Based on the Periodic Table, explain why Na and Khave similar chemical properties

Answers

The Group 1 elements, which include lithium (Li), sodium (Na) and potassium (K) are also known as the alkali metals. They all have one electron in the outer shell and so they have similar properties.

Most metals are in the liquid state at room temperature.

Answers

that statement is False.

Most metals are in the solid state at room temperature. The only metal that is in liquid state in the room temperature is Mercury, (Hg)

Ernest Rutherford's discovery led to the understanding that atoms consist mostly of empty space with

Answers

Answer: With a positively charged nucleus.

Explanation:

HELP PLEASE. Predict the new element formed when u-238 undergoes 2 alpha decay, 1 beta decay, and 1 gamma radiation. Write nuclear equation.

Answers

This hypothetical process would produce actinium-230.

Explanation

An alpha decay reduces the atomic number of a nucleus by two and its mass number by four.

There are two types of beta decay: beta minus β⁻ and beta plus β⁺.

The mass number of a nucleus stays the same in either process. In β⁻ decay, the atomic number increases by one. An electron e⁻ is produced. In β⁺ decay, the atomic number decreases by one. A positron e⁺ is produced. Positrons are antiparticles of electrons.

β⁻ are more common than β⁺ in decays involving uranium. Assuming that the "beta decay" here refers to β⁻ decay.

Gamma decays do not influence the atomic or mass number of a nucleus.

Uranium has an atomic number of 92. 238 is the mass number of this particular isotope. The hypothetical product would have an atomic number of 92 - 2 ⨯ 2 + 1 = 89. Actinium has atomic number 89. As a result, the product is an isotope of actinium. The mass number of this hypothetical isotope would be 238 - 2 ⨯ 4 = 230. Therefore, actinium-230 is produced.

The overall nuclear reaction would involve five different particles. On the reactant side, there is

one uranium-238 atom.

On the product side, there are

one actinium-230 atom,
two alpha particles (a.k.a. helium-4 nuclei),
one electron, and
one gamma particle (a.k.a. photon).

$\;_{\phantom{2}92}^(238) \text{U} \to \;_{\phantom{2}89}^(230) \text{Ac} + \;_(2)^(4) \text{He} + \;_(2)^(4) \text{He} + \text{e}^(-) + \gamma$

Consider: what would be the products if the nucleus undergoes a β⁺ decay instead?

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