Answer:
4.83 km
Explanation:
Let's consider the following subtraction.
4.910 km - 0.08 km
For an addition or a subtraction, the rule for significant figures is as follows: <em>limit the reported answer to the rightmost column that all numbers have significant figures in common</em>, in this case, 2 figures after the decimal point.
4.910 km - 0.08 km = 4.83 km
Explanation:
The work is to calculate the molar mass of the solute (adrenaline) from the elevation of the boling point and compare with the mass of the structural formula. If they both are reasonably equal then you conclude that the results are in agreement, else they are not in agreement.
Since, you did not include the structural formula, I can explain the whole procedure to calculate the molar mass from the boiling point elevation, and then you can compare with the mass of the structural formula that only you know.
Determination of the molar mass from the boiling point elevation.
1) With the elevation of the boiling point, which is a colligative property, you can find the molality of the solution, using the formula:
ΔTb = i * Kb * m
Where:
> ΔTb is the increase of the boiling point of ths solvent, i.e. CCl4.
> i van't Hoff constant = 1 (because the solute is non ionic)
> m is the molality of the solution
2) Clearing m you get:
m = ΔTb / Kb
Kb is a datum that you must find in a table of internet (since the statement does not include it).
I found Kb = 5.02 °C/m
Then, m = 0.49°C / (5.02°C/m) = 0.09760956 m
3) With m and the mass of solvent you find the number of moles of solute using the formula:
m = number of moles of solute / kg of solvent
You have the mass of the solvent = 36.0 g = 0.0360 kg, so you can solve for the number of moles of solute:
=> number of moles of solute = m * kg of solvent = 0.09760956 m * 0.036kg = 0.0035139 moles
4) With the nuimber of moles and the mass you find the molar mass:
molar mass = mass in grams / number of moles = 0.64 g / 0.0035139 moles = 182 g/mol <------------- this is the important result
5) Now that you have the molar mass you can compare with the mass of the molecular formula. If they are reasonably equal then you conclude that the <span>molar mass of adrenaline calculated from the boiling point elevation is in agreement with the structural formula</span>
Answer:
Explanation:
From the information given:
(a)
(b)
(c)
∴
(d)
∴
(e)
∴
∴
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<h3>First we find out the freezing point:</h3>
→(-23.0)-(0.0_
→-23.0 degrees C
<h3>Calculate target Colligative Molarity:</h3>
→ -23=1.86 * Cm
→ 12.37= Cm.
→i* molality
→i= 1
→12.37= 1*m
→12.37= m
<h3>molality= moles of solute(C2H6O2)/kg of solvent water</h3>
12.37m= moles C2H6O2/ 10.0kg water
123.7= moles of C2H6O2
123.7moles C2H6O2 * 62.26g C2H6O2
<h2>= 7701.56 g of C2H6O2</h2>
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Answer:
2H2O2(aq)→ 2H2O(l) O2(g) : The oxidation number of oxygen for each compound is -1, -2, 0
Explanation:
In peroxides the oxidation state of oxygen is -1, since one oxygen bonds to the other oxygen and a hydrogen and the bound oxygen captures the electron of the remaining hydrogen. Through a scheme would be
H --- O --- O --- H
We remember that oxygen needs two electrons to get to have the configuration of the nearest noble gas (Lewis octet rule). In Peroxides, the oxygen is linked by covalent bonds. If we take it strictly, peroxide is a grouping of two oxygen, having the whole valence -2. which is why it is usually said that it is when oxygen has a valence -1
As we said the oxidation state is -2, the one that appears in the water molecule, since Hydrogen acts with valence +1 and it is 2 atoms that give up electrons to compensate for oxygen.
In the O2 it acts with valence 0 since we talk about gas in its elementary state. All diatomic molecules in their elemental state, generally gases or metals in solid state, act with a valence of 0.
