6 Questions with answers on exam-4-study-
guide-part-1pdf
You'll find the list of questions at the end of the document
1. What are the six strong acids that you should know for this exam?
The six strong acids are: Perchloric acid (HClO4), Nitric acid (HNO3),
Sulfuric acid (H2SO4), Hydrochloric acid (HCl), Hydrobromic acid (HBr),
and Hydroiodic acid (HI).
2. Explain the difference between a saturated, unsaturated, and
supersaturated solution.
A *saturated* solution contains the maximum amount of solute that can
dissolve in a given amount of solvent at a specific temperature. An
*unsaturated* solution contains less solute than the maximum amount that
can dissolve, meaning more solute can be added and dissolved. A
*supersaturated* solution contains more solute than the maximum amount
that should dissolve at a given temperature. This is an unstable state, and
the excess solute will often precipitate out of the solution if disturbed or if a
seed crystal is added.
3. A solution of hydrochloric acid (HCl) has a concentration of 0.25
M. What is the pH of this solution?
Since HCl is a strong acid, it completely dissociates in water. Therefore, the
concentration of H3O+ ions is equal to the concentration of HCl, which is
0.25 M. The pH is calculated as -log[H3O+]. So, pH = -log(0.25) = 0.60.
4. What mass of cobalt(III) chloride (CoCl3) is required to make 20.0
mL of a 0.550 M solution?
First, calculate the number of moles of CoCl3 needed: Molarity (M) = moles
of solute / liters of solution. So, moles of CoCl3 = Molarity * Volume (in
liters) = 0.550 mol/L * 0.020 L = 0.011 moles. Next, calculate the molar
mass of CoCl3: Co (58.93 g/mol) + 3 * Cl (35.45 g/mol) = 58.93 + 106.35 =
165.28 g/mol. Finally, calculate the mass of CoCl3 needed: mass = moles *
molar mass = 0.011 moles * 165.28 g/mol = 1.818 g. Therefore, 1.818 g of
cobalt(III) chloride is required.
5. Explain the greenhouse effect and its impact on the environment.
The greenhouse effect is a natural process where certain gases in the
Earth's atmosphere trap heat from the sun. Solar radiation enters the
atmosphere, and some of it is absorbed by the Earth's surface, which then
emits infrared radiation (heat). Greenhouse gases, such as carbon dioxide,
methane, and water vapor, absorb this infrared radiation and re-emit it in
all directions, including back towards the Earth's surface. This process
warms the planet. An increase in the concentration of greenhouse gases,
