Diag 4921 Phys
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- What is the molecular mass of water?
- 18
- Ideal gas: (high/low) pressure and (high/low) temperature; and why?
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Therefore, real gases approach ideality at low
pressures and high temperatures.
Why? B/c at high pressures, however, a gas may be compressed to a point where the volume of the
molecules themselves becomes a significant fraction of the total occupied volume, violating postulate (1). And at low
temperatures, the molecules travel more slowly and forces of attraction can overcome their motion, resulting in a greater
tendency to “stick together†as the molecules collide, violating postulate (2). - What one must assume for ideal gas?
-
(1) that most of the volume of the gas sample is empty space, and (2) that the gas molecules experience
no intermolecular forces. - What would be teh magnetic field produced by a negatively-charged oil droplet moving downward with velocity v?
- The magnetic field created by a moving charge circles around the direction of motion of the charge (in accordance with the right-hand rule).
- What single change to the experimental system would reduce the electric field strength necessary to maintain the oil drop in static equilibrium?
-
When the oil drop (with charge –q) is in static equilibrium, the electric force it feels, qE upward, is balanced by the
gravitational force, mg downward. Thus, qE = mg, so E = mg/q. Either decrease in mass or increase in charge. - T/F: The only way to change a reaction's equilibrium constant is to change the temperature.
- True.
- delta(G)_vapor =
- delta(G)f_gas - delta(G)f_liquid
- How does lnK look?
-
negative for K<1
positive for K>1. - delta(G) = ?
-
delta(H) - T delta(S)
delta(S) = entropy
delta(H) = enthalpy - A reaction that is spontaneous at high temperatures but nonspontaneous at low temperatures must result in:
- increasing entropy and increasing enthalpy;
- Is centripetal acceleration constant?
- No it is constantly changing its direction.
- Ramp with centripetal acceleration: If a car were at rest on the track and then began to slide down as shown above, which one of the following must be true of u_s, the coefficient of static friction btw the car's tires and the track surface?
-
m g sin(theta) > u_s m g cos(theta)
=> u_s < tan(theta) - Give a description of the principal energy conversion that occurs for a voltaic cell that yeilds a current tha travels through a conducting wire situated in a vacuum. After a pd of 1 min, the wire begins to flow and the ambient temperature rises.
-
A voltaic cell uses a spontaneous redox reaction to produce an electric current, and the resistance in the conducting
wire causes some of this electrical energy to be converted into light and heat. Thus, the energy conversion here is chemical
Æ electrical Æ light and heat. - Equation for mirror?
- 1/i + 1/o = 1/f
- What occurs to mp, bp, osmotic pressure, and vapor pressure when a given solute concentration is increased?
-
- Adding the given solute to water will expand the temperature range of its liquid phase by lowering its melting point and raising its boiling point.
- Osmotic pressure (a measure of the tendency to take on water) increases with solute concentration
- The addition of the solute causes vapor pressure depression. - If the boiling point of an aqueous solution increases, what happens to the vapor pressure?
- Decreases b/c vapor pressure is used to describe a liquid's tendency to evaporate.
- What does beta decay do?
- It increases the number of protons by one but leaves the total number of protons and neutrons unchanged.
- What does alpha decay do?
- It decreases the number of protons by 2 and decreases teh total number of protons and neutorns by 4.
- Mass energy equivalence
- E=m c^2
- The amount of mass lost in a fusion reaction is 5 x 10^-29 kg. How much energy is released?
- E = m c^2 where c=3e8
- If the pH is 2, then the concentration of HCl is?
- 0.01M (1e-2)
- What is a buffer?
- A buffer is formed by a mixture of a weak acid and its conjugate base.
- Is stomach fluid a buffer?
-
A buffer is formed by a mixture of a weak acid and its conjugate base.
Stomach fluid, however, is a strong acid (HCl) solution. - (T/F) Stomach fluid is electrically neutral.
- True
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Volume flow rate;
mass of volume -
f = A v;
m = p_fluid A v; - What is the difference between an exponential graph and x^2 graph!
- Self-explanatory.
- What the difference between stress and strain?
- Stress has to do with pressure and strain has to do with change in length.
- The sound level of a sound wave that is striking an eardrum is increased from 35 dB to 55dB. By what factor has the intensity of the sound increased?
- 100
- Light travels faster in water than in benzene. When the interface of each of these liquids with air is considered, then relative to benzene, water will have a:
-
- A smaller index of refraction than benzene and a larger critical angle...
- The critical angle with air (that is, the angle of incidence beyond which an incident beam of light in the medium would experience total internal reflection upon striking the boundary with air) is given by the expression sin–1(1/n), where n is the refractive index of the medium. Since water has a lower refractive index than benzene, the value of 1/n is greater, and
the value of sin–1(1/n) is also greater. - Is AgI(s) <=> Ag+(aq) + I-(aq) a redox reaction?
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No. The oxidation states of Ag and I in AgI(s) are +1 and –1, respectively, and
neither changes during dissolving. - How does freezing point depression relate to solubility?
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Freezing point depression is a colligative property, and, as such, depends directly upon the number of dissolved ions
is solution. If something produces the greater freezing point depression, then it must dissolve more readily. - Why does the solubility of AgI decrease in an aqueous solution if NaI is added (AgI(s) <=> Ag+(aq) + I-(aq)
- The equilibrium described by Reaction 1 will be shifted to the left if more I– ions are present in solution (which would occur if NaI were added), thus increasing the concentration of AgI(s). This phenomenon is known as the common ion effect.
- Common Ion effect
- If we mix a soluble salt containing an ion common to a slightly soluble salt equilibria we will affect the position of the equilibrium of the slightly soluble salt system. Adding the common ion to the salt solution by mixing the soluble salt will add to the concentration of the common ion. According to LeChatelier's Principle that will place a stress upon the slightly soluble salt equilibria (added concentration). The equilibrium will respond so as to undo the stress of added common ion. This means that the equilibria will shift so that the common ion will be reduced which means a shift to the left thus REDUCING the solubility of the slightly soluble salt system.
- Upon oxidation with F2(g), a sample of iron was converted to iron(III) hexafluoride. What is the moleclar formula for this complex?
-
By definition, iron(III) has an oxidation state of +3. Since fluorine has an oxidation state of –1, iron(III) hexafluoride, with formula unit FeF6, would have a total oxidation state of (+3) + 6(–1) = –3. Therefore, this complex must
be an ion with a charge of –3: FeF 3–. - What is the electron configuraiton of cobalt?
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Since cobalt has atomic number 27, the electron configuration must account for 27 electrons.
The passage states that “in general, the (n – 1)d subshell of the transition elements does not start to fill until after the ns
subshell has been filled.†Therefore, we would expect that the electron configuration of a cobalt atom would be described
by [Ar] 4s^2 3d^7. - Which one of the following elements in its pure solid state would be expected to exhibit the highest melting point? (Chromium / Iron / Nickel /Zinc)
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- The transition metals owe their properties to the belated filling of the next-to-outermost energy level; in general, the (n-1)d subshell of the transition elements doesn't start to fill until after the n s subshell has been filled. Conversely, a tupical transition metal will donate teh electrons in its ns subshell to a bond before those in the (n-1)d subshell.
- The strongest bonds are exhibited among the elemnts with the outer electron configuration of (n-1)d^4 ns^2. - A helium balloon is released from the ground and rises 5km vertically while the wind blows it 4km north and 3km east. What is the approximate magnitude of the balloon's displacement?
- 7km. d=sqrt((3^2+4^2)+5^2)
- What is the relationship btw c, lambda, and f?
- c = lambda f
- MegaHz
- hz x 10^6
- A particle w/ a mass of 2g and a charge of 10uC is subjected to an electric field of constant magnitude. The aprticle rises 5cm in 2 seconds. Approximately how much energy was expeneded in lifting the particle?
- 0.5mv^2 + mgh