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The enthalpies of formation of the compounds in the combustion of methane, , are CH4 (g): Hf = –74.6 kJ/mol; CO2 (g): Hf = –393.

algol [13]

Answer:

The amount of energy released from the combustion of 2 moles of methae is 1,605.08 kJ/mol

Explanation:

The chemical reaction of the combustion of methane is given as follows;

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)

Hence, 1 mole of methane combines with 2 moles of oxygen gas to form 1 mole of carbon dioxide and 2 moles of water vapor

Where:

CH₄ (g): Hf = -74.6 kJ/mol

CO₂ (g): Hf = -393.5 kJ/mol

H₂O (g): Hf = -241.82 kJ/mol

Therefore, the combustion of 1 mole of methane releases;

-393.5 kJ/mol × 1 + 241.82 kJ/mol × 2 + 74.6 kJ/mol = -802.54 kJ/mol

Hence the combustion of 2 moles of methae will rellease;

2 × -802.54 kJ/mol or 1,605.08 kJ/mol.

8 0

3 years ago

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2 bromocyclopentanamine structural formula

Elis [28]

Answer:

The structure is given in attached file.

Explanation:

Explanation

2-bromocyclopentamine (Figure attached) is a synthetic compound which is synthesized by substitution reaction of cyclopentamine and hydrobromide. Its molecular formula and molecular mass are C5H10NBr and 164.05 mol/g respectively. It is a very reactive compound so it doesn’t available in pure form, it is present in market as a mixture of 2-bromocyclopentamine and Hydrobromide.

Properties :

Its boiling point is 115 0C

Its melting point is – 75 oC

It is highly flammable

It is highly toxic

It is irritant

It is corrosive in nature

5 0

3 years ago

Which solution is a homogeneous mixture? sand and water salt and water salad dressing soil

Over [174]

Answer: Option (b) is the correct answer.

Explanation:

A solution whose constituent particles are uniformly distributed in the solution is known as a homogeneous solution.

In a homogeneous solution, particles of one solute completely dissolves in the solvent. This solution is also known a true solution.

When sand and water are mixed together then after a certain interval of time sand particles will settle at the bottom. Therefore, they do not dissolve in water. So, it is not a homogeneous solution.

When salt and water are mixed together then the salt particles will dissolve in water. Therefore, it is a homogeneous solution.

Salad dressing is not a homogeneous solution as it contains different solutions like oil, lemon juice etc which does not dissolve when mixed together.

On the other hand, soil is also not a homogeneous solution because we can visualize the distinct layers present in a soil. These layers when mixed in a solution does not dissolve so they did not form a homogeneous solution.

Thus, we can conclude that out of the given options, salt and water is a homogeneous mixture.

8 0

3 years ago

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Which element has a greater electronegativity? fluorine (9) or radium (88)

emmainna [20.7K]

Answer:

Fluorine

General Formulas and Concepts:

Chemistry

Reading a Periodic Table
Periodic Trends
Electronegativity - the tendency for an element to attract an electron to itself
Z-effective and Coulomb's Law, Forces of Attraction

Explanation:

The Periodic Trend for Electronegativity is up and to the right of the Periodic Table.

Fluorine is Element 9 and has 9 protons. Radium is Element 88 and has 88 protons. Therefore, Radium has a bigger Zeff than Flourine.

However, since Radium is in Period 7 while Fluorine is in Period 2, Radium has more core e⁻ than Fluorine does. This will create a much larger shielding effect, causing Radium's outermost e⁻ to have less FOA between them. Fluorine, since it has less core e⁻, the FOA between the nucleus and outershell e⁻ will be much stronger.

Therefore, Fluorine would attract an electron more than Radium, thus bringing us to the conclusion that Fluorine has a higher electronegativity.

7 0

2 years ago

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50 pennies or other coins (all coins must be the same value)

Neko [114]

Hey!

Hope this helps...

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Question 1: Turn 25 coins tails up. You now have 50% parent material and 50% daughter material. What is the half life of this substance? (20 Points)

Answer:

Based upon the given information, we can assume that the half life of this coin material is 5 years.

Question 2: Imagine that another half life has gone by. Remember that ONLY the parent material can change to the daughter material. Turn over your pennies to represent the passing of another half life. How much total parent material and how much total daughter material do you now have? You may express your answer in number of pennies or in %. (Note: Since you cannot turn over half a penny, round the actual number of pennies you would turn over up.) (20 points)

Answer:

Based upon the given information from Question 2 and Question 3, we can assume that 13 additional coins would be turned over. We started with 50, than flipped 50% of them over, and now another 50% over. We have 12 coins left.

Question 3: How many half lives will pass before you have only 3 pennies that are parent material and 47 pennies that are daughter material? (20 Points)

Answer:

Based upon the given information from all the questions, and based upon our answers we can assume this:

1st half-life: 50 turned to 25 coins

2nd half-life: 25 turned to 12 coins

3rd half-life: 12 turns to 6 coins

4th half-life: 6 turns to 3 coins

So, after 4 half-lives (or after 20 years) we would have 3 coins left that have parent material.

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For future reference please do not post as complex questions like this, if you do (post a question that is similar to this) please state the following information:

"All questions posted in this post relate to one-another and cannot be answered without the other questions..."

4 0

2 years ago