Answer:
change in composition
a substance decomposing
burning
Explanation:
A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes (evolution or absorption of energy in form of heat or light or both).
This process is often irreversible.
- Chemical changes involves changes in mass.
- It requires considerable amount of energy.
- It leads to the production of new kinds of matter
Now, processes such as burning and decomposition are chemical changes and are not easily reversible.
Since new kind of matter is formed, there is a change in composition.
Melting is a physical change that is easily reversed.
Other examples of chemical changes are rusting of iron, precipitation and souring of milk.
Answer:
v₂ = 39L
Explanation:
Given parameters:
Initial volume of gas = 20L
Initial temperature = 140K
Unknown:
Final volume = ?
Solution:
Since the standard temperature of any gas is 273K, the final temperature is this 273K;
Applying Charles's law:
= 
v and T are volume and Temperature
= 
v₂ x 140 = 20 x 273
v₂ = 39L
