Answer: 3 Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same
Explanation:
Physical change mainly physical properties of a substance while the chemical changes remain unchanged. Once there is a change to the chemistry of the substance, this would be classified as a chemical change.
Answer:
the molarity is 3.68 moles/L
Explanation:
the molality of the solution of sucrose is
m= moles of glucose / Kg of solvent (water)= 6.81 ,
since the molecular weight of glucose is 180.156 gr/mole , then per each kilogram of solvent there is
6.81 moles*180.156 gr/mole + 1000 gr of water = 2226.86 gr of solution
from the density
volume of solution = mass of solution/density = 2286.86 gr / 1.2 gr/ml = 1855.71 ml
therefore there is 1000 gr of water in 1855.71 ml
then the molarity M is
M= moles of glucose / L of solution = (moles of glucose / Kg of solvent) * (Kg of solvent/L of solution) = 6.81 moles/Kg * 1Kg/1.85 L = 3.68 moles/L
M= 3.68 moles/L
Note:
- Would be wrong in this case to assume density of water = 1 Kg/L since the solution is heavily concentrated in glucose and therefore the density of water deviates from its pure value.
Explanation:
A chemical bond which is formed in between positively charged atoms when there is sharing of free electrons in a lattice of cations is known as a metallic bond.
In a pure metal, atoms are surrounded by free moving valence electrons which move from one part of metal to another.
Thus, we can conclude that pure metals are held together by metallic bonds due to attraction between mobile valence electrons and positively charged metal ions.
