Chem/Phys Flashcards
(28 cards)
1 atm is equal to how many Pascals?
1 atm= 10^5 Pa
Ex) 85kPa = 0.85 atm
What is Dalton’s law of partial pressures?
the total pressure of a mixture of gases is equal to the sum of the partial pressures of its components.
Equations:
Pgas = XgasPtotal (Xgas is mole fraction of gas)
Xgas = ngas/ntotal
Given: height, mass, linear path, no air resistance.
Need: velocity just prior to impact? (V final)
½ m(vfinal)2 = mgΔh
Conservation of energy
KEinitial + PEinitial = KEfinal + PEfinal
What is homotropic regulation?
Homotropic regulation is when a molecule serves as a substrate for its target enzyme and as a regulatory molecule of the enzyme’s activity.
Ex) O2 binding to hemoglobin. If one binding site binds to O2, it increases likelihood that the other sites will too.
How does relative humidity change with temperature?
Higher temperatures have higher relative humidity, lower temperatures have lower humidity (total grams of H20 at given volume).
How many Liters does one mole of gas occupy? (Ideal gas)
22.4L (at 1:1 ratio)
What is the role of indicators in acid-base titrations?
Indicators identify an endpoint by undergoing color change near desired pH. The pKa of a chosen indicator should be within ±1 unit of the target pH.
Substrate Analog
Mimics the substrate of the enzyme causing the enzyme to act on the analog rather than the true substrate
What is a positive control?
A positive control is a control group that is not exposed to the experimental treatment but that is exposed to some other treatment that is known to produce the expected effect.
What is a negative control?
Control group that is not exposed to experimental treatment or any other treatment that is expected to have an effect.
Which phase changes are exothermic processes?
Reactions that go from gas to liquid to solid release heat, which classifies them as exothermic reactions
Known: 10kg mass, rolled down frictionless ramp, 3 meters
Need: Work done to slow the object to the stop?
Work- Joules
No KE at beginning, so just find initial PE
PE=mgh
Work=?
Work= power x time
Work- J
Power- J/s
Time- s
Wavelength is equal to?
λ = hc/E
h- Planck’s constant (6.62x10^-34)
c- speed of light (3x10^8)
How to determine higher Ka
Higher Ka is associated with more acidity. Adding electron-withdrawing functional groups (like fluorine atoms) provides inductive stabilization of the conjugate base, making it more acidic.
Which type of inhibition is irreversible?
Suicide Inhibition
(Competitive, Non-competitive, and Uncompetitive are reversible inhibition)
How can you tell if a transition metal will be colored in solid or aqueous forms?
If the d orbitals are fully filled, it will be colorless.
Titration at equivalence point
NaVa = NbVb, where N and V are the normality (mol/L) and volume of the acidic and basic solutions, respectively. It is important to convert from molarity (M) to normality (N) for polyprotic acids and polyvalent bases.
Given: 0.10 M sodium hydroxide, 15 mL equivalence point, glycine titrated with 20 mL
Need: Molarity of glycine solution?
(15 mL) (0.10 mol/L) (1 glycine/1) (1/20 mL)
Simplify to: (15/20) (0.10) = (3/4) (0.10) = 0.075 moles/L
What is the pKa of amino acids?
All amino acids have a pKa that is approximately 2.5.
What is the isoelectric point?
The isoelectric point is the pH at which the net charge of the amino acid is zero.
As a neutral amino acid, the pI for glycine occurs at the first equivalence point
Bicarbonate buffer system
H2O (aq) + CO2 (g) ⇌ H2CO3 (aq) ⇌ H+(aq) + HCO3− (aq)
Hydrochloric Acid (Ex:10.2 M concentration)
Hydrochloric acid is a strong acid and completely dissociates in aqueous solution.
The pH is the -log of the hydronium ion concentration: -log[10] = -log[101] = -1. While the typical pH range is normally thought of as ranging from 0 to 14, if the hydronium ion concentration is greater than 1 M negative pH values are possible. It is also possible to have pH values greater than 14 if the hydroxide concentration is greater than 1 M.
