CHEM-1055
This type of force is responsible for the attraction between the positive and negative ends of polar molecules?
Dipole-dipole forces
This common unit of concentration is calculated as moles of solute per liter of solution?
What is molarity
According to the Brønsted-Lowry definition, an acid is a substance that does this?
What is donates a proton (H⁺)
At equilibrium, the concentrations of products and reactants are doing this?
What is staying constant
Increasing temperature usually does this to the rate of a chemical reaction.
What is increases it
In the photoelectric effect, no electrons are ejected if the light's frequency is below this value, regardless of intensity?
What is the threshold frequency
The solubility of a gas in a liquid generally does this as temperature increases?
What is decrease
In the reaction:
NH3+H2O
Identify the conjugate acid of ammonia.
What is NH4+
These two phases are not included in equilibrium expressions?
What are solids and liquids
If a reaction is zero order in [A], what happens to the rate when [A] is doubled?
What is nothing — the rate stays the same.
The increase in ionization energy across a period is largely due to this, often abbreviated as Zeff?
What is effective nuclear charge
If you dilute 50.0 mL of a 2.00 M NaCl solution to a final volume of 200.0 mL, what is the new concentration?
What is 0.500 M
Between HF, HCl, and HBr, which is the weakest acid, and why?
What is HF, because fluorine holds onto the proton more tightly due to its high bond strength
Write the equilibrium expression for:
N2+3H2↔2NH3?
What is
K=[NH3]2/[N2][H2]3
A linear plot of ln[A] vs. time indicates the reaction is this order.
What is first order
These two factors determine the magnitude of lattice energy according to Coulomb’s Law?
What are the charge of the ions and the distance between them (ionic radius)
Rank the following in order of increasing water solubility: hexane (C6H14), ethanol (C2H6O), sodium chloride (NaCl)?
What is hexane < ethanol < sodium chloride
Which atom makes a stronger base: nitrogen or oxygen?
What is nitrogen (because it holds electrons less tightly and can share them more easily)
If K>1, which side of the reaction is favored at equilibrium?
What is the product side
Doubling the concentration of reactant A doubles the reaction rate. What is the order with respect to A?
What is first order.
In VSEPR theory, the term "electron geometry" refers to the arrangement of all electron groups. What’s the electron geometry of water (H₂O)?
What is tetrahedral
The dissolution of ammonium nitrate in water is endothermic and leads to an increase in disorder. Predict the sign of ΔH, ΔS, and ΔG?
What is ΔH > 0, ΔS > 0, and ΔG < 0
Between HClO, HClO₂, and HClO₃, which is the strongest acid?
What is HClO₃, because more electronegative oxygen atoms stabilize the conjugate base via resonance
If Q > K, which direction will the reaction shift to reach equilibrium?
What is to the left (toward reactants).
If doubling [A] causes the rate to quadruple, what is the reaction order with respect to A?
What is second order.