Magnetism: separates magnetic materials from non-magnetic. 3rd diagram
evaporation: separates a soluble solid by boiling off. 4th diagram
filtration: separates insolube solid from a liquid. 1st diagram
distillation: separates liquids with different boiling points. 5th diagram
chromatography: separates liquids of different colours. 2nd diagram
1. two or mor, chemically bonded
2. purify
3. magnetism, evaporation, filtration, distillation, chromatography
Answer:
The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol
Explanation:
The ∆H (heat of reaction) of the combustion reaction is the heat that accompanies the entire reaction. For its calculation you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient (number of molecules of each compound that participates in the reaction) and finally subtract them:
Enthalpy of the reaction= ΔH = ∑Hproducts - ∑Hreactants
In this case, you have: 2 NOCl(g) → 2 NO(g) + Cl₂(g)
So, ΔH=
Knowing:
- ΔH= 75.5 kJ/mol
- = 90.25 kJ/mol
- = 0 (For the formation of one mole of a pure element the heat of formation is 0, in this caseyou have as a pure compound the chlorine Cl₂)
- =?
Replacing:
75.5 kJ/mol=2* 90.25 kJ/mol + 0 -
Solving
-=75.5 kJ/mol - 2*90.25 kJ/mol
-=-105 kJ/mol
=105 kJ/mol
<u><em>The standard enthalpy of formation of NOCl(g) at 25 ºC is 105 kJ/mol</em></u>
Here are the key events listed in chronological order with
their corresponding year.
1. Hooke coins the word cell after viewing cork cells with
primitive microscope. (1665)
2. van Leeuwenhoek discovers bacteria with his improved
microscope. (1676)
3. Brown recognizes and names the cell nucleus. (1831)
4. Schleiden & Schwann propose cell theory. (1839)
5. Virchow describes cell division; proposes that all cells
arise from other cells. (1855)
<span>6. Pasteur disproves spontaneous generation and proposes germ
theory. (1861)</span>