What does Hess’s law state?

Answers

Answer 1

Answer: Hess's law states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions comprising it. In other words, the enthalpy change of a chemical reaction (the heat of reaction at constant pressure) does not depend on the pathway between the initial and final states. The law is a variation of the first law of thermodynamics and conservation of energy.

Answer 2

Answer:

Answer:

C. The enthalpy of a reaction is the sum of the enthalpies of intermediate reactions.

Explanation:

The heat of any reaction ΔH∘f for a specific reaction is equal to the sum of the heats of reaction for any set of reactions which in sum are equivalent to the overall reaction.

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Will a precipitate form when NaCl(aq) and AgNO3 (aq) are mixed together?

Answers

yes,because they are both soluble salts so they form an insoluble salt which will be the precipitate formed

Decreasing the temperature can change water vapor into liquid water. What other change might also accomplish this task?A. Increasing the temperature
B. Decreasing the pressure
C. Increasing the pressure

Answers

Answer;

Increasing the pressure

Explanation;

An increase in pressure on a gas can bring the molecules close enough to each other to develop some inter-molecular attractions and form a liquid.
The increase in pressure changes the state of matter from gas to liquid and also from liquid to solid. But increase in pressure alone cannot change the state of matter. Every gases and liquid have certain temperature above which the application of pressure would not change the state of matter.

Decreasing the temperature can decrease the pressire. Temperature is directly proportional to pressure as what the law that Gay-Lussac stated. As the pressure goes increases,the temperature also increases. The higher the energy of a molecule, there is a high temperature and pressure also.

Which element has three unpaired electrons in its p orbital? carbon (atomic number 6) oxygen (atomic number 8) nitrogen (atomic number 7) beryllium (atomic number 4)

Answers

Answer: N (atomic number 7)

Explanation:

1) Due the electron distribution of each, taking into account Hund's rule to deal with pairing of electrons.

2) Hund's rule: each subshell orbital is occupied with single electrons of parallel spin before double occupation occurs.

That is, before any one orbital is doubly occupied, every orbital in a subshell is singly occupied with one electron, and all the electrons in singly occupied orbitals have the same spin, which means that they are unpaired.

3) Distributions:

a) C (atomic number 6) ⇒ 6 electrons:

⇒ 1s² 2s² 2p² ⇒ 1s² 2s² 2p ↑ ↑ : as per Hund's rule the two electrons on 2p are unpaired.

b) O (atomic number 8) ⇒ 8 electrons

⇒ 1s² 2s² 2p⁴ ⇒ 1s² 2s² 2p⇅ ↑ ↑: as per Hund's rule the two 2p electrons are unpaired

c) N (atomic number 7) ⇒ 7 electrons

1s² 2s² 2p³ ⇒ 1s² 2s² 2p↑ ↑ ↑: as per Hund's rule, the three 2p electrons are unpaired, so this is the answer to the question.

c) Be (atomic number 4) ⇒ 4 electrons

⇒ 1s² 2s² ⇒ none p electron.

Final answer:

Nitrogen has three unpaired electrons in its p orbital.

Explanation:

Among the given elements, nitrogen (atomic number 7) has three unpaired electrons in its p orbital.

In the electron configuration of nitrogen, it has a total of five electrons: 2 in the 1st energy level and 3 in the 2nd energy level. The p sublevel of the 2nd energy level contains three orbitals, each capable of holding 2 electrons. Therefore, the three unpaired electrons in nitrogen's p orbital are in three separate p orbitals in the 2nd energy level.

Carbon has two unpaired electrons in its p orbital, while oxygen has two unpaired electrons in its p orbital and two in its s orbital. Beryllium does not have any unpaired electrons in its p orbital.

Learn more about Unpaired electrons here:

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Two or more atoms that have been chemically combined are
called a

Answers

Answer:

compound

Explanation:

Which missing item would complete this beta decay reaction?

Answers

The question is incomplete. Complete question is attached below:
.................................................................................................................

Correct Answer is : 54 131Xe

Reason:
Emission of beta particle from radioactive material increases atomic number by one, but atomic mass number donot change.

In present case, the reactant is 53 131 I. When, iodine emits beta particle i.e. electron, it atomic number increases by one. Hence, it gets converted into Xe. Atomic number of Xenon is 54.

The equation must include the parent and the daughter nucleus as well as the particle emitted.

What is beta decay?

A beta decay is said to occur when an electron is emitted from an atom. In this case, the daughter nucleus is greater in atomic number than the parent nucleus by one unit.

The question is incomplete. However, the equation must include the parent and the daughter nucleus as well as the particle emitted.

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How is the charge of an atom determined?
how is the amount of neutrons determined?

Answers

Atoms have positively charged protons and negatively charged electrons, the number of each tells you the charge.
The ionic charge is the number of protons subtracted by the number of electrons. They usually have the same charge, but with opposite signs, Electrons ( -) and protons ( +)
To find the neutron number,subtract the proton number from the atomic mass. It will give you the neutron number.
Hope this helps.

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