FREE Ultimate AP Chemistry Exam Question and Answers
Helium gas weighs 0.40 g in a 2.0 L flask. What will happen to the helium's entropy if it is evacuated into a bigger container while the temperature is kept constant?
Explanation:
Entropy is a gauge of how disorderly a system is. The gas molecules will spread out and become more disorganized in a larger flask.
High-energy photons hit chlorine neutral atoms, which causes the ejection of electrons from the variably populated subshells. Which subshell's initial electrons would be ejected with the highest velocity?
Explanation:
An electron will have higher kinetic energy once it is released the further it is from the nucleus because less ionization energy is needed to eject it. The furthest subshell in which an uncharged chlorine atom could have electrons is the 3p subshell. There is no 3d subshell in chlorine.
One mole of carbon atoms has an average mass in grams of
Explanation:
The idea behind this is simple to comprehend. According to the periodic table, an element's average atomic mass is expressed as both the average mass of a mole of its atoms in grams and the average mass of a single atom in amu.
Which will most likely have a greater boiling point, propane or ethene, and why?
Explanation:
Both are nonpolar, but propane is more polarizable than ethene because it has a lot more electrons.
What is occurring to the forward reaction's rate at t = 60 s?
Explanation:
A flat line on the graph indicates equilibrium, where all species' concentrations in the process are remaining constant. At equilibrium, the rates of the forward and reverse reactions are both constant.
Which two compounds are most likely to mix with water when in a liquid state?
Explanation:
As "like dissolves like," we might infer that because water is polar, only polar solvents will be able to completely mix with it to produce a homogeneous solution.
Estimate the vapor pressures of each chemical in liquid form at the same temperature, going from highest to lowest based on the strength of the intermolecular forces in each substance.
Explanation:
Intermolecular forces are a determinant of vapor pressure. It is easier for molecules to escape from the liquid's surface when the IMFs are weaker. Polar and nonpolar molecules have different IMF strengths, so let's start there. Both methanol and ethanal are polar, but methanol has stronger IMFs (and hence a lower vapor pressure) than ethanal due to hydrogen bonding. While both ethene and propane are nonpolar, propane is bigger than ethene and therefore more polarizable, which results in stronger IMFs and lower vapor pressure.