A student made a copper bracelet by hammering a small copper bar into the desired shape. The bracelet has a mass of 30.1 grams a
nd was at a temperature of 21°C in the classroom. After the student wore the bracelet, the bracelet reached a temperature of 33°C. Later, the student removed the bracelet and placed it on a desk at home, where it cooled from 33°C to 19°C. The specific heat capacity of copper is 0.385 J/g•K. 69 Explain, in terms of heat flow, the change in the temperature of the bracelet when the student wore the bracelet. [1]
70 Determine the number of moles of copper in the bracelet. [1]
71 Show a numerical setup for calculating the amount of heat released by the bracelet as it cooled on the desk. [1]
72 Explain, in terms of chemical activity, why copper is a better choice than iron to make the bracelet. [1]
69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet.
70. moles of copper=mass of copper/molar mass of copper =30.1g/(63.55g/mol)= 0.4736 moles Cu
Precipitation tends to be HIGHER on the WINDWARD SIDE of the a mountain because water vapour CONDENSES as it rises there. There are two sides to every mountain, the windward and the leeward sides. The windward side experience more rainfall while the leeward side is drier and warmer.
