ANSWER
option B
EXPLANATION
Firstly, we will need to define the standard heat of formation
The standard heat of formation is the amount of heat evolved or absorbed when one mole of a compound is completely formed from its constituent elements under standard conditions.
From the options provided, you will see that only option B aligns with the definition of the standard heat of formation.
From the above reaction, you will see that 1 mole of water is formed from hydrogen and oxygen.
Hence, the answer is option B
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:
Sharing or covalent bonding is taking place.
Explanation:
The valence electron will be shared by both the atoms so that means that the election will move around both of the atoms.
Answer:
Explanation: Circle
Solve for area
A=πr2
onversion result for two surface area units:
From unit Symbol Equals Result To unit Symbol
1 square centimeter cm2 , sq cm = 1.27 ∅ 1-centimeter circles ∅ 1 cm
Amount : 18 ∅ 1-millimeter circles (∅ 1 mm)
Equals : 0.14 square centimeters (cm2 , sq cm)
Fraction : 7/50 square centimeters (cm2 , sq cm)
Nonpolar covalent bonds are a type of chemical bond where 2 atoms share electrons with each other.
Polar covalent bonds are the same as nonpolar covalent bonds, but a pair of electrons are unequally shared between 2 atoms.
Ionic bonds are a type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.
Hope this helps! ^-^
