Exam 14: Temperature and Heat

Pennies used to be made of copper, but now they are made of copper-coated zinc. If one were to do a precise calorimetry experiment to determine the specific heat of the new pennies, what would be the result to be?

Which of the following has the highest specific heat?

Carbon dioxide and water molecules in the atmosphere will absorb:

A 0.2-kg aluminum plate, initially at 20 $\degree$ C, slides down a 10-m long surface, inclined at a 30 $\degree$ angle to the horizontal. The force of kinetic friction exactly balances the component of gravity down the plane so that the plate, once started, glides down at constant velocity. If 90% of the mechanical energy of the system is absorbed by the aluminum, what is its temperature increase at the bottom of the incline? (Specific heat for aluminum is 900 J/kg · $\degree$ C.)

In the text there is a table of coefficients of linear ( ) and volume ( ) expansions due to temperature changes. For the solid materials in this list, there is a relationship between and which allows you to find the value of if you know . Which of the following best describes that relationship?

A machine gear consists of 0.40 kg of iron and 0.16 kg of copper. How much total heat is generated in the part if its temperature increases by 35 $\degree$ C? (Specific heats of iron and copper are 450 and 390 J/kg · $\degree$ C, respectively.)

A steel plate has a hole drilled through it. The plate is put into a furnace and heated. What happens to the size of the inside diameter of a hole as its temperature increases?

A plot of the temperature versus the energy per kg added to a piece of ice as it goes from below freezing at -10 $\degree$ C to becoming steam at 110 $\degree$ C consists of straight lines, some horizontal and some with an upward slope. What do the upward slopes represent?

Which best describes a system made up of ice, water, and steam existing together?

How much heat energy is required to vaporize a 1.0-g ice cube at 0 $\degree$ C? The heat of fusion of ice is 80 cal/g. The heat of vaporization of water is 540 cal/g, and c_water = 1.00 cal/g· $\degree$ C.

Carbon dioxide forms into a solid (dry ice) at approximately -157 $\degree$ F. What temperature in degrees Celsius does this correspond to?

Inside a house, stepping on a tile floor barefooted may feel almost cold, but stepping on carpet in an adjacent room feels comfortably warm. Why is this?

At high noon, the Sun delivers 900 W to each square meter of a blacktop road. What is the equilibrium temperature of the asphalt, assuming its emissivity e = 1? ( $\sigma$ = 5.67*10^-8 W/m²*K⁴) .

The surface of the Sun has a temperature of about 5800 K. If the radius of the Sun is 7*10⁸ m, determine the power output of the sun. (Take e = 1, and $\sigma$ = 5.67 *10^-8 W/m² ·K⁴).

A puddle holds 150 g of water. If 0.75 g of water evaporates from the surface, what is the approximate temperature change of the remaining water? (L_v = 540 cal/g)

When heating 2 kg of ice from , 2 kg of water from , and 2 kg of steam from , which requires the most energy?

Carly places one end of a steel bar in a Bunsen flame and the other end in an ice cube. By what factor is the rate of heat flow changed when the bar's cross-sectional area is tripled?

What happens to a given volume of water when heated from 0 $\degree$ C to 4 $\degree$ C?

A 3.00 g lead bullet is traveling at a speed of 300 m/s when it embeds in a wood post. If we assume that half of the resultant heat energy generated remains with the bullet, what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg· $\degree$ C, 1 kcal = 4186 J)

A solar heated house loses about 7.4 *10⁷ cal through its outer surfaces on a typical 24-hour winter day. What mass of storage rock is needed to provide this amount of heat if it is brought up to initial temperature of 62 $\degree$ C by the solar collectors, and the house is maintained at 20 $\degree$ C? (Specific heat of rock is 0.21 cal/g · $\degree$ C.)