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Inessa [10]
3 years ago
7

For the of freezing liquid ethanol at a given temperature and pressure,A. ΔH is positive and ΔS is positive.B. ΔH is positive an

d ΔS is negative.C. ΔH is negative and ΔS is positive.D. ΔH is negative and ΔS is negative.
Chemistry
1 answer:
Ksivusya [100]3 years ago
3 0

Answer:

ΔH is negative and ΔS is negative.

Explanation:

Endothermic reaction -

The type of reaction in which energy is absorbed in the form of heat is known as endothermic reaction .

The reaction mixture usually get cooled after the reaction .( temperature decreases ) .

The sign of ΔH of an Endothermic  reaction is positive .

<u>For the of process of freezing the liquid ethanol  ,  energy in the form of heat is released and hence , exothermic reaction ΔH is negative  .</u>

<u>In the process of freezing , liquid is converted to solid , i.e. , the randomness reduces , and hence , entropy also decreases , hence , ΔS is negative .</u>

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Can someone help.? thanks :)​
laila [671]

Answer:

  • <u>1. Equation: 2x  + 3 = 9x - 11</u>

<u></u>

  • <u>2. Each row has 2 chairs</u>

Explanation:

The variable x represents the number of chairs in each row.

<u />

<u>1. She can form 2 rows of a given length with 3 chairs left over.</u>

Thus, she has:

number of rows  number of chairs in      chairs             number of chairs

                             each row                       left over         she has

     2                        x                                    3                      2x + 3

<u>2.  She can form 9 rows of the same length if she gets 11 more chairs.</u>

That means that she is short in 11 chairs to have 9x chairs, or that she has 11 less chairs than 9x chairs. Then she has:

  • 9x - 11

<u>3. Equation:</u>

Then, number of chairs she has is 2x + 3 and, also, 9x - 11, which allows to set the equation:

  • 2x + 3 = 9x  -11

<u>4. Solve the equation:</u>

  • 9x - 2x = 3 + 11
  • 7x = 14
  • x = 2

Therefore, each row has 2 chairs, and she has 2x + 3 = 4 + 3 = 7 chairs.

4 0
3 years ago
mixture or pure substance: 1.blood 2.dyes 3.self-raising flour 4.muesli 5.copper wire 6.distilled water 7.table salt 8.milk 9.br
jenyasd209 [6]

Answer: Mixture: Blood , Self raising flour,muesli ,dyes, milk, tea, air, bronze

Pure substance: Copper wire, distilled water, table salt, oxygen.

Explanation:

Mixture is a substance which is made up two or more number of compounds which chemically inactive and retain their distinct chemical properties.

Blood , Self raising flour,muesli ,dyes, milk, tea, air, bronze

Pure substance is defined as anything with uniform and unchanging composition is known s pure substance.

Copper wire, distilled water, table salt, oxygen.

5 0
3 years ago
Can you guys give some science fair project ideas(8th grade)
Anton [14]
Answer
i’m in 7th grade but for this years science fair i did, “ how does temperature affect the elasticity of rubber bands”

Guide a growing plant through a maze.
8th Grade Science Plant Maze KiwiCo

Prove that plants really do seek out the light by setting up a simple or complex maze. This is a simple 8th grade science project with really cool results.

Blow out a candle with a balloon.


Blowing up a balloon with baking soda and vinegar is the classic acids and bases experiment. Take it a step further by experimenting with the carbon dioxide it produces. (Don’t be afraid of fire in the science

Stand on a pile of paper cups.


Combine physics and engineering and challenge 8th grade science students to create a paper cup structure that can support their weight. This is a cool project for aspiring architects.

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5 0
3 years ago
Use the balanced equation to solve the problem.
harkovskaia [24]

Answer:

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Explanation:

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1 N₂ + 3 F₂ ---> 2 NF₃

2.10 moles N₂        2 moles NF₃
---------------------  x  ---------------------  =  4.20 moles NF₃
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7 0
2 years ago
How do nervous and muscular work together
kirza4 [7]

Answer:

the nervous system tells the muscles what to do beause your nervous sytem is hooked up to your brain

Explanation:

4 0
2 years ago
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