The weight of an object is constant. true false
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<u>Answer:</u> The freezing point of solution is -0.454°C
<u>Explanation:</u>
Depression in freezing point is defined as the difference in the freezing point of pure solution and freezing point of solution.
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 = 0°C
i = Vant hoff factor = 2
= molal freezing point elevation constant = 1.86°C/m
= Given mass of solute (KCl) = 5.0 g
= Molar mass of solute (KCl) = 74.55 g/mol
= Mass of solvent (water) = 550.0 g
Putting values in above equation, we get:
Hence, the freezing point of solution is -0.454°C
Answer:
.
Explanation:
Carbon and hydrogen are the only two elements in a hydrocarbon. When a hydrocarbon combusts completely in excess oxygen, the products would be and
. The
and
would come from the hydrocarbon, while the
atoms would come from oxygen.
Look up the relative atomic mass of these three elements on a modern periodic table:
:
.
:
.
:
.
Calculate the molar mass of and
:
.
Calculate the number of moles of molecules in
of
:
.
Similarly, calculate the number of moles of molecules in
of
:
.
Note that there is one carbon atom in every molecule. Approximately
of
molecules would correspond to the same number of
atoms. That is:
.
On the other hand, there are two hydrogen atoms in every molecule. approximately
of
molecules would correspond to twice as many
atoms. That is:
.
The ratio between the two is: .
The empirical formula of a compound gives the smallest whole-number ratio between the elements. For this hydrocarbon, the empirical formula would be .