No, the number of particles does not change as the substance changes its state.
<h3><u>Explanation: </u></h3>
Change of state from one phase to another is achieved by providing or absorbing heat or pressure. For instance, liquid water if heated becomes vapour steam and if cooled becomes solid ice. Vapour can be compressed to form liquid water again and thus change of state is a reversible action.
The "chemical composition of the matter remains the same" irrespective of its state. Unless a chemical change is carried out, no change occurs with the number of particles. Phase change only affects the "arrangement of molecules", its structure and its motion.
Answer: The symbol representing the result of a gas expanding against a constant pressure is W
Explanation:
According to first law of thermodynamics, energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.
The mathematical form of first law of thermodynamics is:

where
= change in internal energy
q = heat absorbed or released
W = work 
P = pressure
= volume change
Thus the changes in heat or work leads to change in internal energy.
Answer:
The maximum height is 2881.2 m.
Explanation:
Given that,
Acceleration = 29.4 m/s²
Time = 7.00 s
We need to calculate the distance
Using equation of motion

Put the value into the formula


We need to calculate the velocity
Using formula of velocity

Put the value into the formula


We need to calculate the height
Using formula of height

Put the value into the formula


We need to calculate the maximum height
Using formula for maximum height

Put the value into the formula


Hence, The maximum height is 2881.2 m.
Answer:
Explanation:
When objects collide, energy can be transferred from one object to another, thereby changing their motion. In such collisions, some energy is typically also transferred to the surrounding air; as a result, the air gets heated and sound is produced.