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3 years ago

Explain the changes that take place at the molecular level when a substance is superheated or supercooled ?

1 answer:

4 0

Only gas or vapor can be superheated. Use water as an example. Water at sea level boils at 212 degrees F. When heated to 212 degrees F, the molecules that make up water are moving at a high enough speed that they overcome the air pressure above the water. And for supercooled only liquids or solids can be supercooled for example Liquid water at sea level has a saturation (boiling) temperature of 212 degrees F. If we were to add heat to the saturated water, it would first boil away with no change in temperature (remember latent heat?) and then become superheated if still more heat were added to the vapor (steam) after it had all turned to a vapor.

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How are radar and an approaching siren different? How are they similar?

Irina-Kira [14]

Answer:

Explanation:

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3 years ago

In neutron moderation, neutrons are slowed down so that:

erastovalidia [21]

B. Nuclear fission reactions are slowed down as well.

Neutron moderation is a substance which slows down neutron. In some reaction moderator is same as coolant.

This is also used to slow down nuclear fission reaction and continue chain reactions.

The collision between neutron and nuclei is more elastic and more neutrons will be slowed due to size of the neutron.

Learn more at brainly.com/question/24371385

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3 years ago

Using the following standard reduction potentials, Fe3+(aq) + e- → Fe2+(aq) E° = +0.77 V Ni2+(aq) + 2 e- → Ni(s) E° = -0.23 V ca

lina2011 [118]

Answer: The above reaction is non-spontaneous.

Explanation:

For the given chemical reaction:

$Ni^{2+}(aq.)+2Fe^{2+}(aq.)\rightarrow 2Fe^{3+}(aq.)+Ni(s)$

Here, nickel is getting reduced because it is gaining electrons and iron is getting oxidized because it is loosing electrons.

We know that:

$E^o_{(Fe^{3+}/Fe^{2+})}=0.77V\\E^o_{(Ni^{2+}/Ni)}=-0.23V$

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

$E^o_{cell}=-0.23-0.77=-1.0V$

Relationship between standard Gibbs free energy and standard electrode potential follows:

$\Delta G^o=-nFE^o_{cell}$

As, the standard electrode potential of the cell is coming out to be negative for the above cell. Thus, the standard Gibbs free energy change of the reaction will become positive making the reaction non-spontaneous.

Hence, the above reaction is non-spontaneous.

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3 years ago

In the formula for the compound XCl4, the X could represent (1) C (3) Mg (2) Η (4) Zn

Anvisha [2.4K]

Correct Answer: option 1 i.e. C

Reason:
The the compound of interest i.e. XCl4, since there are 4 Cl atoms bonded to X. This signifies that the valency of X is 4.

There atomic number of C is 6. It's electronic configuration is giving by 1s2 2s2 2p2. Thus, there are 4 electrons in valence shell of C. This signifies that valency of C is 4. Hence the compound present in present case is CCl4.

7 0

3 years ago

Read 2 more answers

Penicillinase, also known as β‑lactamase, is a bacterial enzyme that hydrolyzes and inactivates the antibiotic penicillin. Penic

sergeinik [125]

Explanation:

The given data is as follows.

$V_{max} = 6.8 \times 10^{-10} \mu mol/min$