false all element when they are combined eachother thier valance number will change
the combination of oxygen and aluminum gives us Al2O3 see even the numbers are changing thank you if you have a comment you can write
Valence electrons is the answer to ur question
Answer : The molal freezing point depression constant of liquid X is, 
Explanation : Given,
Mass of urea (solute) = 5.90 g
Mass of liquid X (solvent) = 450 g = 0.450 kg
Molar mass of urea = 60 g/mole
Formula used :

where,
= change in freezing point
= freezing point of solution = 
= freezing point of liquid X = 
i = Van't Hoff factor = 1 (for non-electrolyte)
= Molal-freezing-point-depression constant = ?
m = molality
Now put all the given values in this formula, we get


Therefore, the molal freezing point depression constant of liquid X is, 
Answer:
C. Boiling water
Explanation:
Boiling water is a physical change only; the H20 molecules are moving from a liquid state to a gas state and not turning into a new substance.