Answer:
Answer: Chemical change; Chemical property of heat of combustion
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
Explanation:
1) Independent variable is the physical properties
2) Dependent variable is the pH of the solution.
You can change the physical properties (independent variable) to get a different pH value(dependent variable)
Answer is: c. MgSO₃.
In magnesium sulfite, magnesium has oxidation number +2, sulfur has oxidatidion number +4 and oxygen -2:
+2 + (+4) + 3·(-2) =0.
a) in calcium sulfide, calcium has oxidation number +2 and sulfur -2:
+2 + (-2) = 0.
b) in sodium nitride, sodium has oxidation number +1 and nitrogen -3:
3 · (+1) + (-3) = 0.
d) in aluminium nitrite, aluminium has oxidation number +3, nitrogen +3 and oxygen has -2:
+3 + (+3 + 2 · (-2)) · 3 = 0.
Ok to answer this question we firsst need to fin the number of mol of Urea (CH4N2O). to do this we simply :
1 mol of urea =15/60.055 = 0.25mol
therefore 200g of water contain 0.25mol
the next step is to determine the malality of our solution in 200g of water, to do this we say:
200 g = 1Kg/1000g = 0.2kg
therefor 0.25mol/0.2Kg = 1.25mol/kg
and from the equation:
we know that i = 1
we are given Kf
b is the molality that we just calculated
therefore;
the solutions freezing point is -2.325°C
