All elements have a AHf, of <u>0</u>
kJ/mole at standard temperature and pressure.
<h3>What is an element?</h3>
An element can be defined as a substance which cannot be split into two or more simpler forms by an ordinary chemical process
Below are the list of the first twenty elements:
- Hydrogen
- Helium
- Lithium
- Berylium
- Boron
- Carbon
- Nitrogen
- Oxygen
- Fluorine
- Neon
- Sodium
- Magnesium
- Aluminum
- Silicon
- Phosphorus
- Sulphur
- Chlorine
- Argon
- Potassium
- Calcium
So therefore, all elements have a AHf, of <u>0</u>
kJ/mole at standard temperature and pressure.
Learn more about elements:
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Explanation:
The given data is as follows.
Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml
- Therefore, molarity of toulene is calculated as follows.
Molarity = 
= 
= 4.11 M
Hence, molarity of toulene is 4.11 M.
- As molality is the number of moles of solute present in kg of solvent.
So, we will calculate the molality of toulene as follows.
Molality = 
= 
= 8.6 m
Hence, molality of given toulene solution is 8.6 m.
- Now, calculate the number of moles of toulene as follows.
No. of moles = 
= 
= 0.8227 mol
Now, no. of moles of benzene will be as follows.
No. of moles =
= 
= 1.2239 mol
Hence, the mole fraction of toulene is as follows.
Mole fraction = 
= 
= 0.402
Hence, mole fraction of toulene is 0.402.
- As density of given solution is 0.857
so, we will calculate the mass of solution as follows.
Density = 
0.857 = 
(As 1 
= 1 g)
mass = 171.4 g
Therefore, calculate the mass percent of toulene as follows.
Mass % = 
= 
= 44.22%
Therefore, mass percent of toulene is 44.22%.
Answer:
18 liters
Explanation:
Step 1: Figure out what the formula and what you are dealing with.
- 25 degrees celcius is constant, so it is irrelevant for the mathmatical part.
- P1 = 1 atm
- P2 = 20 atm
- V1 = 360 liters
- V2 = trying to find
Note: remember the original equation is V1/P1 = V2/P2
- Step 2: Rearrange the equation to fit this problem, you should get...
V2 = V1 x P1 / P2
- Step 3: Fill our own numbers in. You should get...
360 L x 1 atm / 20 atm = 18 Liters (do the math)
- Answer = 18 Liters
- Remember to just follow the formula and fill it in with your own numbers.
If you need any more help comment below. I am happy to help anytime.
Answer:
why is there a cherry on its head?
Explanation:
You may want to add details/description to the photo as it is a little confusing
Here we apply the Clausius-Clapeyron equation:
ln(P₁/P₂) = ΔH/R x (1/T₂ - 1/T₁)
The normal vapor pressure is 4.24 kPa (P₁)
The boiling point at this pressure is 293 K (P₂)
The heat of vaporization is 39.9 kJ/mol (ΔH)
We need to find the vapor pressure (P₂) at the given temperature 355.3 K (T₂)
ln(4.24/P₂) = 39.9/0.008314 x (1/355.3 - 1/293)
P₂ = 101.2 kPa
