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4 years ago

Given the balanced equation representing a phase change:

Chemistry

2 answers:

aliina [53]4 years ago

8 0

Answer: (2) It is endothermic, and entropy increases.

Explanation: Endothermic reactions are those in which heat is absorbed by the system and exothermic reactions are those in which heat is released by the system.

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

In the given reaction:

$C_6H_4Cl_2(s)+energy\rightarrow C_6H_4Cl_2(g)$

The energy is absorbed by the reactants and thus it is endothermic and the solid reactants are converting to gaseous products, thus the entropy increases.

pochemuha4 years ago

7 0

The answer is (2). The energy is at left of the equation, so it absorbs energy. It is called endothermic. And the entropy is a measure of disorder. The disorder degree of gas is more than solid. So the entropy increases.

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Why do health care professionals limit the number of radiation treatments that a person can be given

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4 years ago

Which term is described as a long, narrow depression in the ocean floor?

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3 years ago

Read 2 more answers

Which of the procedures, if either, is more accurate when making a 1/501/50 dilution of a solution? Transfer 1 mL1 mL with a pip

nikitadnepr [17]

Full question:

First of all, bear in mind that this question is incomplete. Here is the full question:

Which of the procedures, if either, is more accurate when making a 1/50 dilution of a solution?

a) Transfer 1 mL with a pipet into a 50-mL volumetric flask.

b) Transfer 20 mL with a pipet into a 1-L volumetric flask.

c) Both procedures have the same accuracy.

How can the accuracy of either procedure be improved?

a) Use an Erlenmeyer flask instead of a volumetric flask.

b) Use a graduated cylinder instead of a pipet for the transfer.

c) Calibrate each piece of glassware.

d) Instead of using a 1/50 dilution to make the solution, weigh out the material on a balance and transfer ir directly to the volumetric flask.

Answer:

1) c) Both procedures have the same accuracy.

2) c) Calibrate each piece of glassware.

Explanation:

1) Given that the 1/50 relation is maintained whether we pour 1 mL into a 50-mL volumetric flask or we transfer 20 mL with a pipet into a 1-L volumetric flask, both procedures have the same accuracy (because in both procedures we are using volumetric glassware).

When we want the most exact result possible, we need to calibrate the volumetric glassware used (bear in mind that the only volumetric glassware is the buret, the volumetric flask, the micropipet and the pipet). This is usually done measuring the mass of water poured by the recipient or contained in it, and using the density of that liquid to convert mass into volume. In this way is possible, for example, to determine that a pipet poured 10.016 mL and not 10.000 mL.

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3 years ago

2. Ultraviolet radiation has a frequency of 6.8 x 10'5Hz. Calculate the energy, in

Gnoma [55]

Answer:

$E=4.5\times 10^{-18}\ J$

Explanation:

It is given that, the frequency of Ultraviolet radiation is $6.8\times 10^{15}\ Hz$

We need to find the energy of the photon. The formula for the energy of a photon is given by :

$E=hf\\\\\text{Where h is Planck's constant}\\\\E=6.63\times 10^{-34}\times 6.8\times 10^{15}\\\\E=4.5\times 10^{-18}\ J$

So, the energy of the photon is $4.5\times 10^{-18}\ J$ .

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3 years ago

What are The advantages of using scientific procedures in doing science experiments?

Studentka2010 [4]

Answer:

Doing experiments by scientific procedures is advantageous and helpful.

Explanation:

The scientific procedure should be followed while performing a experiment as it has many advantages like:

Working in safe environment: Performing a experiment by scientific procedure ensures the safety of the experimenter.

It reduces the chances of mistakes: The proper availability of the scientific equipment helps in reduction of the chances of the mistakes.

A sequence of steps is followed: A proper sequence of steps is followed to perform a experiment step by step. Performing experiment without scientific procedure may cause the experimenter to forgot a step.

More Accuracy: The readings of the experiment is more accurate by doing experiment by scientifically.

Chemical changes can be observed: The physical and chemical changes can be observed and can be measured by the lab equipment to perform more accurately.

less chance of risks: Performing in the safe scientific environment and using proper safety equipment reduces the chances of risks to the experimenter.

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4 years ago