Answer:
The change that took place is a chemical change as a chemical reaction occurs.
Vinegar = 
Baking soda = 
Reaction:

Answer:
c
Explanation:
The law of conservation clearly states that energy can neither be created nor destroyed
Its tetrahedral since there's four chlorine molecules around carbon
Answer:
Ground state
Explanation:
Ground state is the lowest energy level of particle. In this state toms are stable.
When transition occur from lower energy level to higher energy level require a gain of energy. Electron could not jump into higher energy level without gaining thew energy.
When electron jump into lower energy level from high energy level it loses the energy.
The process is called excitation and de-excitation.
Excitation:
When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits.
De-excitation:
When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum.
Answer:
1540.8 Joules of energy is required to bring a 30 gram crayon from room temperature, 25 degrees C, to its melting point 49 degrees C
Explanation:
Crayon is paraffin wax. The specific heat of paraffin wax is 2.14 J/g°C
As we know

Where
is the change in temperature 
m is the mass of the object
c is the specific heat in J/g°C
Substituting the given values, we get -
Joules
1540.8 Joules of energy is required to bring a 30 gram crayon from room temperature, 25 degrees C, to its melting point 49 degrees C