Answer: Freezing point of a solution will be 
Explanation:
Depression in freezing point is given by:

= Depression in freezing point
i= vant hoff factor = 1 (for non electrolyte)
= freezing point constant = 
m= molality

Weight of solvent (benzene)= 1480 g =1.48 kg
Molar mass of solute (octane) = 114.0 g/mol
Mass of solute (octane) = 220 g



Thus the freezing point of a solution will be 
Answer:
NiCO3 (s) + 2H+ (aq) → H2O (l) + CO2 (g) + Ni2+ (aq)
Explanation:
To write the complete ionic equation:
1. Start with a balanced molecular equation.
2. Break all soluble strong electrolytes (compounds with (aq) beside them) into their ions
3. indicate the correct formula and charge of each ion
4. indicate the correct number of each ion
5. write (aq) after each ion
6. Bring down all compounds with (s), (l), or (g) unchanged.
Answer:
Percent composition tells you which types of atoms (elements) are present in a molecule and their levels. Percent composition can also tell you about the different elements present in an ionic compound as well.