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3 years ago

Which piece of evidence would prove that a reaction is exothermic?

2 answers:

4 0

The reactants have more energy than the products. If a reaction is EXOthermic, it loses energy during the reaction, so the output (products) will have less energy than the input (reactants).

timofeeve [1]3 years ago

3 0

Answer: Option (c) is the correct answer.

Explanation:

In an exothermic reaction, excess of energy is released into the surroundings as a result there occurs decrease in the energy of products.

For example, $A + B \rightarrow C + D + Heat$ is an exothermic reaction.

Whereas in an endothermic reaction, energy is absorbed by reactant molecules and therefore, energy of products is more than energy of reactants.

For example, $A + B + Heat \rightarrow C + D$ is an endothermic reaction.

Thus, we can conclude that the reactants have more energy than the products is a piece of evidence that would prove that a reaction is exothermic.

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5. What is metallic bonding?<br> 6. Why are metals shiny?

cricket20 [7]

Answer:

Metallic bonding is found in metals and their alloys. When the atoms give up their valence electrons, they form ions. These ions are held together by the electron cloud surrounding them. Metals are shiny because they have a lot of free (i.e. delocalized) electrons that form a cloud of highly mobile negatively charged electrons on and beneath the smooth metal surface in the ideal case. ... In the absence of any external EM field, the charges in the plasma are uniformly distributed within the metal.

Explanation:

In metallic bonding, the electrons are “surrendered” to a common pool and become shared by all the atoms in the solid metal.

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3 years ago

Before entering the cyclotron, the particles are accelerated by a potential difference V. Find the speed v with which the partic

vesna_86 [32]

Answer:

Speed, $v=\sqrt{\dfrac{2qV}{m}}$

Explanation:

The device which is used to accelerate charged particles to higher energies is called a cyclotron. It is based on the principle that the particle when placed in a magnetic field will possess a magnetic force. Just because of this Lorentz force it moves in a circular path.

Let m, q and V are the mass, charge and potential difference at which the particle is accelerated.

The work done by the particles is equal to the kinetic energy stored in it such that,

$qV=\dfrac{1}{2}mv^2$

v is the speed with which the particles enter the cyclotron

So,

$v=\sqrt{\dfrac{2qV}{m}}$

So, the speed with which the particles enter the cyclotron is $v=\sqrt{\dfrac{2qV}{m}}$ . Hence, this is the required solution.

7 0

3 years ago

What are the balanced chemical equations for Hydrochloric acid and potassium hydroxide?

-Dominant- [34]

HCl(aq) + KOH(s) --> KCl(aq) + H2O(l)

7 0

3 years ago

In the PhET simulation window, click the radio button labeled Mystery in the Blocks menu on the right-hand side of the screen. U

Yuliya22 [10]

Answer:

B, D, E, C, A

Explanation:

We have 5 blocks with their respective masses and volumes.

Block Mass Volume

A 65.14 kg 103.38 L

B 0.64 kg 100.64 L

C 4.08 kg 104.08 L

D 3.10 kg 103.10 L

E 3.53 kg 101.00 L

The density (ρ) is an intensive property resulting from dividing the mass (m) by the volume (V), that is, ρ = m / V

ρA = 65.14 kg / 103.38 L = 0.6301 kg/L

ρB = 0.64 kg / 100.64 L = 0.0064 kg/L

ρC = 4.08 kg / 104.08 L = 0.0392 kg/L

ρD = 3.10 kg / 103.10 L = 0.0301 kg/L

ρE = 3.53 kg / 101.00 L = 0.0350 kg/L

The order from least dense to most dense is B, D, E, C, A

4 0

3 years ago

what is the correct conversion factor by which to multiply to convert moles of nitrogen to moles of ammonium nitrate (NH4NO3)

Ostrovityanka [42]

Answer:

0.5

Explanation:

1 mole of ammonium nitrate contains 2 moles of nirogen

1 mole of nitrogen converts to 0.5 moles of ammonium nitrate

the conversation factor is 0.5

6 0

3 years ago

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