The given reaction above is an example of <em>single replacement reaction. </em>This is a certain type of reaction in which an element of a compound is replaced by a free element. In this case, chlorine (Cl) is replaced by calcium (Ca).
Explanation:
We will calculate the gravitational potential energy as follows.

= 
= 1164000 J
or, = 1164 kJ (as 1 kJ = 1000 J)
Now, we will calculate the change in potential energy as follows.

=
= 
= -873000 J
or, = -873 kJ
Thus, we can conclude that change in gravitational potential energy is -873 kJ.
Cell, tissue, organ, organ sytem, organism, population, community, ecosystem, biome.
Answer:
The last one, nicotine from tobacco
Answer:
1 / f = 1 / i + 1 / o thin lens equation
1 / i = 1 / f - 1 / o = (o - f) / (o * f)
i = o * f / (o - f)
i = 54.2 * 12.7 / (54.2 - 12.7) = 16.6 cm image distance
Image is real and inverted and 16.6 / 54.2 * 6 = 1.94 cm tall