Answer:
Chemical Change
Explanation:
It became white and became solid which makes it a chemical change.
The solubility of a given solute in a given solvent typically depends on temperature. Many salts show a large increase in solubility with temperature. ... A few, such as cerium(III) sulfate, become less soluble in water as temperature increases.
Answer:
There is one single covalent bond between two carbon atoms.
Explanation:
We know that sharing of electrons form covalent bonds.
If we look upon K,L,M ,N shells of the carbon and hydrogen atoms.
We found that Hydrogen is having only 
electron in K shell.
And Carbon on the other hand is having 
electrons in K shell and 
electrons in L shell.
So carbon have valence electrons,and it can share bonds with any relevant atom to complete its octet.
And Hydrogen requires electron to complete its doublet.
Alkane general formula 
For ethane 
Carbon atom is shared by 
Hydrogen.
The remaining one electron 
of carbon will be shared with another carbon atom.
An image of the sharing of electrons attached below,
Hence we have only covalent bond between the two.
Water can exist in three states.
1) Solid State: Called Ice.
2) Liquid State: Called Liquid Water.
3) Gas State: Called Steam.
Remember:
The physical states of a matter depends upon the interactions between the particles of that substance. The interactions are very strong in solid state, strong in liquid state and very weak or negligible in gas state.
If you want to change the state from solid to liquid, or from liquid to gas you will have to provide energy in order to break the interactions between the molecules. Stronger the interactions, the more is energy required to break the interactions.
Water need more energy to convert from liquid to gas phase because hydrogen bond interactions are present among the molecules of water. And the hydrogen bonds are strong enough. Hence in order to break these interactions high energy is required.
Amu valie on the top and abundsnce percent in decimals on the bottom for each isotope
