Mark Worthy - Physics 2 Exam 3
An ideal gas undergoes an isothermal process. Which of the following statements are true? (i) No heat is added to or removed from the gas. (ii) The internal energy of the gas does not change. (iii) The average kinetic energy of the molecules does not change.
(ii) and (iii) only.
Two ideal gases, A and B, are at the same temperature. If the molecular mass of the molecules in gas A is twice that of the molecules in gas B, the molecules' root-mean-square speed is
1.4 times greater in B
About what percentage of the heat produced by burning gasoline is turned into useful work by a typical automobile?
20%
A heat engine operates between a high temperature of about 600∘C∘C and a low temperature of about 300∘C∘C. What is the maximum theoretical efficiency for this engine?
34%
Which of the following is not true about an ideal gas?
All gas molecules have the same speed at a particular temperature
When using the ideal gas law, which of the following rules must be obeyed?
Always use temperature in kelvins and absolute pressure.
For objects at thermal equilibrium, which of the following is true?
Each is at the same temperature.
Which statement is true regarding the entropy change of an ice cube that melts?
Entropy increases
Which beaker is the coldest, or are they equal in temperature? (one has more ice, same size beaker)
Equal
When you put an ice cube in a glass of warm tea, which of the following happens?
Heat flows from the tea into the ice cube.
Which of the following happens when a material undergoes a phase change?
Heat flows into or out of the material.
Which of the following possibilities could increase the efficiency of a heat engine or an internal combustion engine?
Increase the temperature of the hot part of the system and reduce the temperature of the exhaust. Decrease the temperatures of both the hot part and the exhaust part of the system by the same amount.
Ten grams of water is added to ten grams of ice in an insulated container. Will all of the ice melt?
More info needed
On a very hot day, could you cool your kitchen by leaving the refrigerator door open?
No, the heat exhausted by the refrigerator into the room is more than the heat the refrigerator takes out of the room.
When an ideal gas is warmed from 20∘C to 40∘C< the gas's temperature T that appears in the ideal gas law increases by a factor
Of 1.07
If bottle B has twice the volume and contains half the number of moles of gas as bottle A< how does the pressure in B compare with the pressure in A?
PB=1/4PA
An ideal gas undergoes an isothermal expansion from state A to state B. In this process
Q > 0, delta U = 0, W > 0
Rod A has twice the diameter of rod B, but both are made of iron and have the same initial length. Both rods are now subjected to the same change in temperature (but remain solid). How would the change in the rods' lengths compare?
Rod A = Rod B
Two equal-mass liquids, initially at the same temperature, are heated for the same time over the same stove. You measure the temperatures and find that one liquid has a higher temperature than the other. Which liquid has the higher specific heat?
The cooler one
In a mixture of the gases oxygen and helium, which statement is valid?
The helium atoms will be moving faster than the oxygen molecules, on average.
A steel plate has a hole in it with a diameter of exactly 1.0 cm when the plate is at a temperature of 20 ∘C> A steel ring has an inner diameter of exactly 1.0 cm at 20 ∘C. Both the plate and the ring are heated to 100 ∘C. Which statement is true?
The hole in the plate and the opening in the ring get larger.
If the objects are brought into thermal contact, which one will have the greater temperature change?
The one with the lesser mass.
The temperature of an ideal gas increases. Which of the following is true?
The pressure, the volume, or both, may increase.
It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it is nighttime. The water is cold! The next day, you go swimming again during the hottest part of the day, and even though the air is warmer the water is still almost as cold. Why?
Water has a high specific heat.
The linear expansion of a material depends on which of the following?
all of the above (length, change in temp, type)
An ideal gas undergoes an adiabatic expansion, a process in which no heat flows into or out of the gas. As a result,
both the temperature and pressure of the gas decrease.
Radiation is emitted
by any object not at 0 K.
A typical thermos bottle has a thin vacuum space between the shiny inner flask (which holds a liquid and the shiny protective outer flask, often stainless steel. The vacuum space is excellent at preventing
conduction and convection
One mole of an ideal gas in a sealed rigid container is initially at a temperature of 100 ∘C. The temperature is then increased to 200 ∘C. The pressure in the gas
increases by about 25%
Heat is
the amount of energy transferred between objects as a result of a difference in temperature.
An ideal gas is in a sealed rigid container. The average kinetic energy of the gas molecules depends most on
the temperature of the gas
An ideal gas undergoes an isobaric compression and then an isovolumetric process that brings it back to its initial temperature. Had the gas undergone one isothermal process instead,
the work done on the gas would be greater.
The rms speed of the molecules of an ideal gas
will increase as the temperature of a gas increases
In an isobaric compression of an ideal gas,
work is done on the gas.
As heat is added to water, is it possible for the temperature measured by a thermometer in the water to remain constant?
yes if it is changing phase
