Answer:
B. It undergoes a physical change.
Explanation:
Hello there!
In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
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Answer:
\frac{dh}{dt}_{h=2cm} =\frac{40}{9\pi}\frac{cm}{2}
Explanation:
Hello,
The suitable differential equation for this case is:

As we're looking for the change in height with respect to the time, we need a relationship to achieve such as:

Of course,
.
Now, since the volume of a cone is
and the ratio
or
, the volume becomes:

We proceed to its differentiation:

Then, we compute 

Finally, at h=2:

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Answer:
Explanation:
Discussion
When Pressure increases equilibrium shifts to the side with the smallest number of moles. But which side is that?
N2(g) + 3H2(g) ⇌ 2NH3(g)
The left side has 1 mol of nitrogen (N2) and 3 moles of Hydrogen = 4 mols
on the left side.
The right side has 2 mols of NH3 = 2 mols on the right.
Conclusion: You tell the number of mols by the Balance numbers to the left of each chemical in an equation.
Since the left side N2 + 3H2 = 4 mols, the equilibrium does NOT shift left.
2NH3 is only two mols.
The equilibrium shifts Right
Answer
D
Chemists have developed insulation.