Question

In order to determine the number of kcal (food calories) in a teaspoon of sugar, we can do the following experiment in a bomb calorimeter. A 4.2 g sample of sucrose (1 teaspoon of sugar) is placed into a bomb calorimeter and burned in the presence of oxygen gas. The heat capacity of the calorimeter is 4.90 kJ/°C. The temperature of the water in the calorimeter rises from 23.6 °C to 37.8 °C. What is the value of qv in kJ? kJ What is this value in kcal (food calories)? kcal Let's say we place 25.0 mL of 1.0 M aqueous HCl in a coffee-cup calorimeter and measure the temperature to be 18.5 °C. We quickly add 25.0 mL of 1.0 M NaOH solution and this causes the temperature to rise to 25.0 °C. Assume that the density of the solution is that of water (1.00 g/mL) and that Csoln = 4.46 J/g·°C. What is qrxn for the reaction? J (Report this number with 5 sig. figs. as it is an intermediate step to our solution.) What is ΔHrxn for the reaction? kJ/mol (Use the correct number of sig. figs. for this answer.)

          In order to determine the number of kcal (food calories) in a teaspoon of sugar, we can do the following experiment in a bomb calorimeter. A 4.2 g sample of sucrose (1 teaspoon of sugar) is placed into a bomb calorimeter and burned in the presence of oxygen gas. The heat capacity of the calorimeter is 4.90 kJ/°C. The temperature of the water in the calorimeter rises from 23.6 °C to 37.8 °C.

What is the value of qv in kJ? kJ
What is this value in kcal (food calories)? kcal

Let's say we place 25.0 mL of 1.0 M aqueous HCl in a coffee-cup calorimeter and measure the temperature to be 18.5 °C. We quickly add 25.0 mL of 1.0 M NaOH solution and this causes the temperature to rise to 25.0 °C. Assume that the density of the solution is that of water (1.00 g/mL) and that Csoln = 4.46 J/g·°C.

What is qrxn for the reaction? J (Report this number with 5 sig. figs. as it is an intermediate step to our solution.)
What is ΔHrxn for the reaction? kJ/mol (Use the correct number of sig. figs. for this answer.)

Added by Kelly H.

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