Answer:
Compound B has greater molar mass.
Explanation:
The depression in freezing point is given by ;
..[1]
Where:
i = van't Hoff factor
= Molal depression constant
m = molality of the solution
According to question , solution with 5.00 g of A in 100.0 grams of water froze at at lower temperature than solution with 5.00 g of B in 100.0 grams of water.
The depression in freezing point of solution with A solute:
Molar mass of A =
The depression in freezing point of solution with B solute:
Molar mass of B =
As we can see in [1] , that depression in freezing point is inversely related to molar mass of the solute.
This means compound B has greater molar mass than compound A,
Answer : The enthalpy of the reaction is, -2552 kJ/mole
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given enthalpy of reaction is,
The intermediate balanced chemical reactions are:
(1)
(2)
(3)
(4)
Now we have to revere the reactions 1 and multiple by 2, revere the reactions 3, 4 and multiple by 2 and multiply the reaction 2 by 2 and then adding all the equations, we get :
(when we are reversing the reaction then the sign of the enthalpy change will be change.)
The expression for enthalpy of the reaction will be,
Therefore, the enthalpy of the reaction is, -2552 kJ/mole
Answer:
C. 100.7 amu
Explanation:
Isotopes of an element are atoms of an element with the same atomic number but different atomic masses. Each atomic mass of an isotope is known as an isotopic mass. An element that exhibits isotope, that is, that have two or more isotopes has a relative atomic mass that is not a whole number.
Relative atomic mass of X is the sum of the products of the relative abundances of each isotope and its isotopic mass.
For Isotope ¹⁰⁰X: 30% × 100 = 30 amu
For Isotope ¹⁰¹X: 70% × 101 = 70.7 amu
Relative atomic mass of X = (30 + 70.7) amu = 100.7 amu
Therefore, the approximate atomic mass of X is 100.7 amu
<u>Answer:</u> The freezing point of solution is 5.35°C
<u>Explanation:</u>
The equation used to calculate depression in freezing point follows:
To calculate the depression in freezing point, we use the equation:
Or,
where,
Freezing point of pure solution = 5.5°C
i = Vant hoff factor = 1 (For non-electrolytes)
= molal freezing point elevation constant = 4.90°C/m
= Given mass of solute (naphthalene) = 2.60 g
= Molar mass of solute (naphthalene) = 128.2 g/mol
= Mass of solvent (benzene) = 675 g
Putting values in above equation, we get:
Hence, the freezing point of solution is 5.35°C
The method that can be used to separate the mixture is DISTILLATION.
Distillation is a separating technique that is used to separate mixture of liquids which have boiling points that are far apart. The mixture will be heated, the liquid with the lowest boiling point will boil over and can be collected over a condenser, thus separating the two liquids.