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3 years ago

Determine the energy associated with an e- in hydrogen at n=1 and also at n=t?

Chemistry

1 answer:

Ede4ka [16]3 years ago

5 0

Answer:

hydrogen atom when it drops from N 5 to N 2?

so, 275 kJ of energy is released when one mole of electrons "falls" from n = 5 to n = 2. E = hc/λ (this energy corresponds to the energy of one photon; the energy calculated in this problem is for one mole of photons so we will change this after we change the units from kJ to J)

Explanation:

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Which human activity would most likely decrease the amount of carbon in the atmosphere?

Allushta [10]

The removal of trees would most likely decrease the amount of carbon in the atmosphere.

Please note that it is useful to add the options provided with the question, in order to get a most accurate answer and have your question answered quicker.

Hope this helps!!

6 0

4 years ago

Read 2 more answers

Based on the information given, classify each of the pure substances as elements or compounds, or indicate that no such classifi

Olenka [21]

Answer:

Analysis with an elaborate instrument indicates that:

Substance A contains two elements.

Compound

Substance B and substance C react to give a new substance D.

Insufficient information

Substance E decomposes upon heating to give substance F and substance G.

Compound

Heating substance H to 1000 °C causes no change.

Insufficient information

Substance I cannot be broken down into simpler substances by chemical means.

Element

Substance J cannot be broken down into simpler substances by physical means

Insufficient information

Explanation:

Important background:

Pure substances are elements or compounds.

Elements are formed by only one kind of atoms. They cannot be broken down into another substance by chemical or physical means. There are only 118 known elements; they are all listed in the periodic table.

Compounds have fixed chemical composition and are formed by two or more kind of atoms, chemically bonded. They can be broken down into different pure substances, either elements or other substances, only by chemical changes.

With tha information let's see every statement about the pure substances that should be classified as elements or compounds.

Substance A contains two elements: compound

Since, the pure substance contains two elements, it is not just and element by a compound. This is because a compound is a pure substance composed of two or more elements.

Substance B and substance C react to give a new substance D.: Insufficient information

Either two elements, one element and one compound, or two compounds may react to give a new substance, so you cannot assure what kind of pure substance B and C are.

For instance:

- two elements like hydrogen and oxygen reacto to give water (a compound)

- a compound like CH₂=CH₂ react with an element like Cl₂ to give CH₂Cl-CH₂Cl

Substance E decomposes upon heating to give substance F and substance G. : Compound

An element cannot be decomposed into two different substances, since the elements are composed by just one kind of atoms.

So, if the substance E decomposes into two different substances, F and G, E necessarily has to be a compound.

Heating substance H to 1000 ∘C causes no change. Insufficient information

The mere fact that a substance has not changed by heating at such extreme temperature cannot assure whether the substance is a compound or an element.

Some compounds are stable at very high temperatures. For instace, magnesium oxide, MgO, has a melting point of 2852°C, meaning that it will remain a a solid substance way beyond 1,000°C

Substance I cannot be broken down into simpler substances by chemical means. Element

Since an element is formed by one single kind of atoms, it cannot be broken down into simpler substances by chemical means; but a compose does, because it is formed by two or more different elements chemically bonded.

Substance J cannot be broken down into simpler substances by physical means: Insufficient information

The distintion between compounds and elements is based on chemical changes; the fact that physical changes do not change the substance does not tell anything about the fact that the substance is composed by one kind of elements or several elements chemical boonded.

Hence, physical means do not provide sufficient information to conclude about whether a substance is an element or a compound.

4 0

3 years ago

What is the mass number of a carbon atom which has 7 neutrons?

Strike441 [17]

Answer:

Carbon-13

Explanation:

Carbon have three isotopes. Isotopes are the atoms of the same element which has a different number of neutrons. Carbon has 3 isotopes.

Carbon-12 : 6 electrons I 6 protons I 6 neutrons

Carbon-13 : 6 electrons I 6 protons I 7 neutrons

Carbon-14 : 6 electrons I 6 protons I 8 neutrons

5 0

3 years ago

What is wrong with the notation 1s22s22p63s23p63d104s24p2 for germanium (atomic number 32)?

Vaselesa [24]

The notation is not written in the correct order as the 4s subshell should appear before the 3d subshell.
The correct order in an electron configuration would be:
1s , 2s , 2p , 3s , 3p , 4s , 3d , 4p , 5s , 4d , 5p , 6s , 4f , 5d , 6p ,..
So, for germanium the electronic configuration should be;
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p²

3 0

3 years ago

Sean drew this diagram and labeled an unknown gas A. Which gas does A represent?

Aneli [31]

The Correct answer is Carbon dioxide CO2.

The Explanation:

according to the diagram:

we can see that the arrows which going to A are from:

1- respirition of the tree . and the CO2 gas is the result and produced gas from respiration.

2- The Combustion went from Home : and the CO2 gas is also the produced gas from the combustion process.

∴ (A) refers to CO2 (carbon dioxide) gas.

4 0

4 years ago

Read 2 more answers