Thermodynamics mix25

The condition of thermal equilibrium between two objects is that the two objects.

• have the same temperature.

• have the same volume.

• have the same area.

• have the same pressure.

• be of the same material.

Body A is at a higher temperature than Body B. When they are placed in contact, heat will flow from A to B

• only if the thermal conductivity of A is greater than that of B

• only if A has the greater internal energy content

• only if the specific heat of A is larger that that of B

• only if the volume of A is larger than that of B

• until both have the same temperature

Which one of the following statements is wrong?

• Most solid materials contract when cooled

• Generally liquids expand more than solids for the same temperature change

• If two bodies are in thermal equilibrium than they must have the same temperature

• The density of most substances decreases when they are heated

• Two bodies can be in thermal contact for a very long time without being in thermal equilibrium

Which of the following statements is True:

• When the temperature of an object increases by one degree-C it means that it has increased by less than one degree-F.

• 272 Kelvin is warmer than zero degree-C.

• If two objects are in thermal equilibrium they must have the same temperature

• if an object (A) is warmer than a second object (B) in the Fahrenheit scale then object (B) must be warmer than object (A) in the Celsius scale.

• The coefficient of linear ex 4nsion is the same for all materials.

A 20-g ice cube at 0 degree C is heated until 15 g has become water at 100 degree C and 5.0 g has been converted to steam. How much heat is added to do this? (L(melting)=80 cal/g, L(vaporization) = 540 cal/g, c(water) = 1 cal/g/C ).

• 3300 cal.

• 6300 cal.

• 5200 cal.

• 9000 cal.

• 2300 cal.

What mass of steam (T = 100 degrees-C) is required to melt 200 g of ice and produce water at 25 degrees-C? (c(water)= 1 cal/g*degrees-C, Lf=79.7 cal/g, Lv=539 cal/g.)

• 34.1 g

• 22.5 g

• 121 g

• 254 g

• 145 g

How much heat is required to melt ice of mass 500 g at -10 deg C to water at 0 deg C? (specific heat of ice, c_i = 2220 J/(kg.K); heat of fusion of ice, L_fi = 333*10³ J/kg )

• 8.45*10⁵ J

• 9.05*10⁵ J

• 1.78*10⁵ J

• 2.05*10⁵ J

• 3.01*10⁵ J

Two cubes, one silver and one iron, have the same mass and temperature. A quantity Q of heat is removed from each cube. Which one of the following causes the final temperature of the cubes to be different?

• latent heat of vaporization

• density

• coefficient of volume expansion

• volume

• specific heat

The work done in the expansion of a gas from an initial to a final state.

• always equals P(V_f-V_i).

• depends only on the end points.

• is the slope of a PV curve.

• is the area under the curve of a PV diagram.

• is negative.

Which of the following statements are CORRECT:

1.  The first law of thermodynamics represents the conservation of energy.

2.  Room temperature is about 20 degrees on the Kelvin scale.

3.  A calorie is approximately 4.2 J.

4.  Heat has the same units as work.

5. Heat is a temperature difference.

• 1, 3, and 4.

• 3 and 5.

• 1 and 5.

• 1, 2 and 3.

• 2 and 4.