A cup initially contains a mixture of 50 grams of ice and 50 grams of water at 0
ID: 1488841 • Letter: A
Question
A cup initially contains a mixture of 50 grams of ice and 50 grams of water at 0 degrees Celsius. The cup is perfectectly insulated so that no heat can transfer in or out. Room temperature is 25 degrees Celsius A small coffee cup heater inside the cup allows heat to be transferred to the ice and water mixture. Heat is transferred at a steady rate and the mixture is stirred continuously so that the temperature is always uniform throughout the mixture. For each question below, choose the shape of the temperature-time graph from the graphs A through F on the previous page that best correspond to the temperature of the mixture during the time interval described. If you think no graph is appropriate, write H. (You may choose a graph more than once. The origin of the graphs does not necessarily represent 0 degree C.) Which graph could show a time interval when the ice is melting but there is still some ice in the water? Which graph could show a time interval when there is still some ice at the beginning of the time interval, but all the ice disappears before the end of the interval? Which graph could show a time interval when there is only water (the ice is completely melted before the time interval begins), but no boiling occurs during the interval? Which graph could show a time interval when the water is boiling during the entire time shown by the graph?Explanation / Answer
20) For This, graph F.
Because, for still ice in that, there must be some low temp. after time t.
21) A& B
Because, when the total ice convert into water, then temp. increases fastely as shown A& B.
22) D.
When there is only water from starting, then temp. increases fastely as shown D.
23) F
Since, when the water is boiling, then the temp. constant at 100oC as shown in F.