Anion means negatively charged ion.
Among Ar, K, Al and O, only O forms anion.
Hope this helps!
Mountains are built by tectonic processes that cause portions of the Earth's crust to rise. These processes are fueled by the escape of heat from the interior of the Earth, causing crustal uplift by volcanic activity and by movement along faults that, in turn, is responsible for the formation of mountains.
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>
Answer:
ΔH = -22 kcal
Step-by-step explanation:
N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + 22 000 cal
Energy is on the right-hand side of the equation, so it is being <em>released</em> by the system.
The thermodynamic convention is that <em>energy going out of a system is negative.</em> Thus,
ΔH = -22 000 cal Convert to kilocalories
ΔH = -22 kcal
A and B are both wrong, because you divide by 1000 to convert calories to kilocalories.
C is wrong, because the sign must be negative for an exothermic reaction.