Attractive Forces and Sticky Situations
This type of intermolecular force occurs between two polar molecules where hydrogen is bonded to fluorine, oxygen, or nitrogen.
What is hydrogen bonding?
What is the osmotic pressure of a 0.20 M NaCl solution at 20°C?
(R = 0.0821 L·atm/mol·K)
What is 9.61 atm?
(Π = iMRT = 2 × 0.20 × 0.0821 × 293)
For the reaction A → B, if [A] drops from 0.80 M to 0.20 M over 4 minutes, what is the average rate of disappearance of A?
What is –0.15 M/min?
(Average rate = Δ[A]/Δt = (0.20 – 0.80) / 4 = –0.60 / 4)
In a zeroth-order reaction, the concentration drops from 0.46 M to 0.03 M in 0.65 hours. What is the half-life of this reaction?
What is 0.325 hours?
At equilibrium, how do the rates of the forward and reverse reactions compare?
What is they are equal?
This property refers to the attraction between unlike molecules and is responsible for capillary action.
What is adhesion?
What is the freezing point of a solution containing 2.0 mol of NaCl in 1.0 kg of water?
(Kf = 1.86 °C/m)
What is −7.44°C?
(ΔTf = i × Kf × m = 2 × 1.86 × 2.0)
A reaction shows that doubling the concentration of a reactant results in quadrupling the rate. What is the order with respect to that reactant?
What is second order?
For a first-order reaction with a rate constant k=0.564 s−1
and an initial concentration of 1.5 M, what is the concentration after 5.0 seconds?
What is 0.0073 M?
Write the expression for Kc for the reaction:
A (aq) +2B (aq) ⇌5C (aq) +(1/2)D (L)
Kc= [C]^5 / [A][B]^2
These solids have an orderly, repeating arrangement of their particles and are often demonstrated in a dedicated educational video.
What are crystalline solids?
What is the boiling point of a solution prepared by dissolving 1.0 mol of NaCl in 2.0 kg of water?
(Kb = 0.512 °C/m)
What is 100.512°C?
(m = 1.0 mol / 2.0 kg = 0.5 m; ΔTb = 2 × 0.512 × 0.5 = 0.512°C; 100 + 0.512 = 100.512°C)
Given the experimental rates for the reaction:
Rate 1: [NO] = 0.10 M, [O₂] = 0.10 M → Rate = 3.0 × 10⁻⁴
Rate 2: [NO] = 0.20 M, [O₂] = 0.10 M → Rate = 1.2 × 10⁻³
What is the order of the reaction with respect to NO?
What is second order?
A second-order reaction has k=0.5 M
and starts with a Molar concentration of [A]0 = 1.5
what is the concentration [A]t = 5.0s
What is 0.316 M
CO(g)+3H2(g)⇌CH4(g)+H2O(g)
What is the value of Δn used to convert between Kc and Kp?
What is –2?
The vapor pressure of ethanol is 44.6 mmHg at 293 K, and its enthalpy of vaporization is 38,560 J/mol. What is the vapor pressure at 323 K?
What is 170 mmHg?
(Use the Clausius-Clapeyron equation: ln(P₂/P₁) = –ΔHvap/R × (1/T₂ – 1/T₁). Answer requires plugging in values and solving.)
How many grams of NaCl are needed to prepare 1.0 L of a 0.28 M solution, assuming you dilute from a 1.6 M stock and want to calculate how much solute ends up in the final diluted solution?
What is 16.36 g of NaCl?
(Use M1V1 = M2V2 → V1 = (0.28×1.0)/1.6 = 0.175 L → moles = 0.28 mol → grams = 0.28 × 58.44)
Using the rate law Rate = k[NO]²[O₂], and the data point [NO] = 0.10 M, [O₂] = 0.10 M, Rate = 3.0 × 10⁻⁴ M/s, calculate the rate constant k.
What is k = 0.30 M⁻²s⁻¹?
(k = Rate / ([NO]²[O₂]) = 3.0×10⁻⁴ / (0.10² × 0.10) = 3.0×10⁻⁴ / 0.001)
A reaction has k1=0.104 at 25°C and k2=0.402 at 80°C.
What is the activation energy in joules?
What is 43,156 J/mol?
N2O5(g)⇌N2O4(g)+O2(g)
If [N₂O₅] = 0.30 M, [N₂O₄] = 5.00 M, and [O₂] = 1.75 M, what is the value of Kp at 50°C?
What is 29.17?
This type of force exists in all molecules, even nonpolar ones, due to temporary fluctuations in electron distribution.
What are London dispersion forces?
You dissolve 5.0 g of sugar in 150 g of water. What is the mass percent of sugar in the solution?
What is 3.23%?
(Mass % = (5.0 / (5.0 + 150)) × 100)
Given the rate law Rate = k[CO][O₂]² and k = 0.10 M⁻²s⁻¹, calculate the rate when [CO] = 0.30 M and [O₂] = 0.30 M.
What is 0.0027 M/s?
(Rate = 0.10 × 0.30 × 0.30² = 0.10 × 0.30 × 0.09)
If k2=1.25 at 90°C and Ea=125 kJ/mol, what is the rate constant at 25°C?
What is 4.4 × 10⁻⁶
In the reaction A+B ⇌C+D
ΔH = –20°C. If temperature increases, in which direction will the reaction shift?
What is to the left?
Since the reaction is exothermic, heat acts as a product. Increasing temperature adds more to the products side, so the equilibrium shifts left.