Question

1. A sample of solid chromium is heated with an electrical coil. If 85.0 Joules of energy are added to a 11.3 gram sample and the final temperature is 39.2 °C, what is the initial temperature of the chromium?

2. She heats 18.6 grams of copper to 97.81 °C and then drops it into an insulated cup containing 80.2 grams of water at 24.17 °C. When thermal equilibrium is reached, she measures the final temperature to be 25.67 °C.

Assuming that all of the heat is transferred to the water, she calculates the specific heat of copper to be ___ J/g°C.

Answer 1

Solution (1) In this question, we use equation :- - q = MCAT - (is q = heat energy m- mass CF specific heat. copacity - AT = Change in temperature - Final Temp. (If I - Initial Temp (T;)] According to question, we have q = 85.0 joules , m = 11.3g Specific heat capacity of chromium = 0.455 19.6. Final temperature = 39.2°c. so, From equation (i) 85.01 = 11:39 x 0.45ylgic (39.2°C - T;) → 16.76 = (39.2°C - T;) so Initial Temperature (Ti) = 22.44 cl

22. In this question Copper we have weeter y mass of copper = 18.6 g Initial temperature a = 97.810 - Final Temp. = 25.67°C specific heat capacity of - copper = ? mass of water = 80. 2g Initial Temperature - 24.7°C 1 Final Temp. = 25.67 °C I specific heat capacity of water = 4.18u Jlg.°c So, In this - question, we use q = mc AT equation Here, ur use relation. - Heat lost by copper = - heat gain by water lo 3 so, q for copper - Veomber - 18.6g x copper x (25-676 -97.81c - so, q for water, q water = 80.2g x 4.184 Ilgic X (25.67°C -24.176 qwater = 503.3352 I So from realtion cis . | 18.69 x Cobber X (-72,140) = - 503.3352] copper = 503.33521 18.69 x (72.140) C'copper = 0.375 Ig.cl