A block of copper of mass 500 g and initially at 293 K is in thermal contact with an electric heater of resistance \(1.00 \mathrm{k} \Omega\) and negligible mass. A current of 1.00 A is passed for 15.0 s. Calculate the change in entropy of the copper, taking \(C_{p, \mathrm{m}}=24.4 \ \mathrm{JK}^{-1} \ \mathrm{mol}^{-1}\). The experiment is then repeated with the copper immersed in a stream of water that maintains the temperature of the copper block at 293 K. Calculate the change in entropy of the copper and the water in this case.
Text Transcription:
1.00komega
C_p,m = 24.4 JK^-1mol^-1
GASES I. Pressure is the force exerted per unit area by gas molecules as they strike the surfaces around them. The total pressure exerted by a gas depends on several factors including the concentration of gas molecules. A. As volume increases, pressure goes down. This results in fewer molecular collisions, resulting in lower pressure. When volume decreases, pressure increases. B. Because of pressure, we can drink from straws, inflate basketballs, and breathe. Variation in pressure in earth’s atmosphere creates wind, and changes in pressure can help us to predict weather. 1. Pressure that a gas exerts is the force that results from the collisions of gas particles divided by the area of the surface with which they collide. 2. The pressure exerted by a gas sample depends on the number of gas particles in a given volume. The fewer particles, the lower the force per unit area and the lower the pressure. Pressure decreases with an increasing altitude. 3. Pressure is measured in several different units. A common unit of pressure, the millimeter of mercury (mmHg), also called a torr, originates from how pressure is measured with a barometer (and evacuated glass tube, the tip of which is submerged in mercury. The liquid mercury is forced upwards by atmospheric pressure. a. Another unit of pressure is the atmosphere (atm), the average pr
