Answer:
At the melting point, some molecules overcome the forces of attraction. Energy gained after the the solid melts increases the average kinetic energy or the temperature. When liquid is freezing the energy flows out the the liquid. As the kinetic energy decreases, they move more slowly.
Explanation:
Answer: The net change in the atoms is the conversion of a neutron to a proton, turning Carbon (6 protons) into Nitrogen (7 protons).
Explanation:
Carbon-14, generated from the atmosphere, has 6 protons and 8 neutrons. That's where the 14 comes from, called the mass number, is the sum of protons and neutrons (6+8=14).
Carbon-14 is radioactive and decays by beta decay. That means one of its neutrons spontaneously turns into a proton, an electron, and a neutrino, according to:

After that, the atom has 7 protons and 7 neutrons, maintaining its mass number but changing its atomic number from 6 to 7, turning into Nitrogen.
Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
Explanation:
A change that leads to the change in chemical composition of a substance is called a chemical change.
For example, 
Here, bond between the reactant atoms nitrogen and hydrogen is broken down.
On the other hand, bond connecting the products that is
and
is formed.
Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.
3-pentanone to form 3-pentanol
Here 3-pentanone reacts with H2/Pt to given 3-pentanol
So here with one step we can convert given ketone to alcohol
The reaction will be