Answer:
0.018 moles of isooctane must be burned to produce 100 kJ.
Explanation:
When the isooctane is <em>burned</em>, it undergoes a reaction known as combustion, in which reacts with oxygen to produce carbon dioxide and water. In standard conditions (Pressure = 1 atm and Temperature = 298 K) formed water is liquid. The balanced equation is:
C₈H₁₈(l) + 12.5 O₂(g) ⇄ 8 CO₂(g) + 9 H₂O(l)
The standard enthalpy of combustion (which can be found in tables) relates the amount of isooctane that reacts and the heat the reaction liberates. In this case, ΔH°c = -5,460 kJ/mol, that is every 1 mol of isooctane that burns, 5,460 kJ of heat are released.
We can begin with the information of 100 kJ and apply this conversion factor. Since this energy is released, by convention, we write it with a minus sign.
Evaporation is used to separate a soluble solid from a liquid. For example, copper sulfate is soluble in water – its crystals dissolve in water to form copper sulfate solution. During evaporation, the water evaporates away leaving solid copper sulfate crystals behind.
Answer:
9.999x10^-7M
Explanation:
First, let us calculate the concentration of the hydrogen ion in both cases:
For pH 6:
pH = —Log [H+]
6 = —Log [H+]
—6 = Log [H+]
Take the anti-log of —6
[H+] = 1x10^-6M
For pH 10:
pH = —Log [H+]
10 = —Log [H+]
—10 = Log [H+]
Take the anti-log of —10
[H+] = 1x10^-10M
The difference between the [H+] of pH 6 and [H+] of pH 10 is given by:
1x10^-6 — 1x10^-10 = 9.999x10^-7M
The epidermis, the top layer
The dermis, middle layer
The hypodermis, bottom layer
There you go!