Question

CHEMA 161 Stanzel Name: Calorimetry Homework Complete the following and turn in at the beginning of class on Thursday, October 31". You must show ALL of your work 1. The specific heat of octane, CH., is 2.22 J/gK. a. How many of heat are needed to raise the temperature of Boog of octane from 10.0 to 25.0°C? b.Which will require more heat, increasing the temperature of 1 mol of octance by a certain amount or increasing the temperature of 1 mol of liquid water by the same amount? Explain your answer using words or calculations. 2. When a 6.50 g sample of solid sodium hydroxide dissolves in 100.0 g of water in a coffee-cup calorimeter (figure 5.18 in your textbook), the temperature rises from 91.6 to 378 C. a. Calculate the quantity of heat (in kJ) released in the reaction (the dissolving of NaOH). b. Using the result from part a, calculate the enthalpy of the reaction for the solution of NaOH in IJ/mol NaOH. 3. A 2.200 g sample of quinone (C.H.0.) is burned in a bomb calorimeter whose total heat capacity is 7.854 kJ/°C. The temperature of the calorimeter increases from 23.44 to 30.57°C. a. What quantity of beat was produced by the combustion of the quinone? b. What is the heat of combustion per gram of quinone? c. What is the heat of combustion per mole of quinone?

Answer 1

Answer

I lay feat energy required com be calculated as follows - q = MCAT & & mass specific Tampereture change heat AT E T - Ti 125 + 273 K - (10 + 273 k). q- 80 9 x 2.22 319.k x 15k 2664 I molar molar mass of octane mass of water = 114.23 g mai = 18.015 g mal I for water = 4.184 J/g.k a needed for water = (18.015 g) (4.18 4 J/g. K) AT - (75.374 AT) J & needed for octore - (14 23 g, (2-22 J/g.K) AT = (253.59 AT) I octane will require more heat Heating