Answer is: It expands when it freezes.
When molecule frezes, it lose energy. When molecules are far apart, it means the volume is greater and it expands.
For example, ice expands when water is freezing.
Hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (H), covalently bound to a highly electronegative atom such as flourine (F), oxygen (O) and nitrogen (N) atoms.
Answer:
Just go out there and be yourself brother!
Explanation:
If she doesn't like you, she doesn't like the real you, therefore you don't deserve her! lol
(2) boiling of water
(3) subliming of ice
(4) decomposing of water
Answer:
Option 4 = decomposing of water
Explanation:
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible.
These changes occur due to chemical reactions.
These may not be observed with naked eye.
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood
Boiling of egg: that change the chemical composition of protein in the egg
The reaction of Hydrogen and oxygen:
H 2 (g) + O 2 (g) -------------------------------------> 2H 2O (l)
Physical Change
The changes that occur only due to change in shape or form but their chemical or internal composition remain unchanged.
These changes were reversible.
They have same chemical property.
These changes can be observed with naked eye.
Example
Water converting to Ice.
Water converting to gas.
In this water molecule remain the same only they rearrange themselves that change its state of mater not composition.
1 = Melting of ice
The melting of ice is physical change because water molecules are just change the state from solid to liquid and composition remain same.
2 = Boiling of water
It is also a physical change because water molecules are just change the state from liquid to gas and the molecular structure of water molecules remain same.
3 = Subliming of ice
It is physical change because ice is converted into water vapors without going through liquid phase.
4 = Decomposing of water
It is a chemical change because water molecules are split into the hydrogen and oxygen. The molecular structure is changed. New product is formed which is different from the reactant.
Answer: 7.8 moles of NaCl result from the complete reaction of 3.9 mol of
Explanation:
To calculate the moles :
As is the excess reagent, is the limiting reagent as it limits the formation of product.
According to stoichiometry :
1 mole of gives = 2 moles of
Thus 3.9 moles of will give= of
7.8 moles of NaCl result from the complete reaction of 3.9 mol of