Energy Basics

Enthalpy

Hess's Law

Calorimetry

Trivia

100

Inside of a beaker, there is a reaction occuring with a temperature of 320 K. The temperature of the room is 298 K. Is this system an open, close, or isolate one AND, assuming the temperatures will reach equilibrium, is the heat flow going to be endothermic or exothermic?

100

A system with a volume of 5.0 L has its volume decreased to 2.0 L under constant pressure of 1.2 atm. Calculate the work of this process in Joules.

360 J

100

If the enthalpy for a synthesis reaction was found to be 24.5 kJ, what would the enthalpy for the reverse reaction, in Joules?

-24500

100

What is the specific heat of water with the correct units?

4.184 J/g-K

100

200

Calculate the kinetic energy of a 6.72 g marble that moves at a velocity of 2.45 cm/s.

2.02 x 10-6

200

At a constant pressure, is the enthalpy or the internal energy equal to heat absorbed or released?

Volume = work so internal pressure = enthalpy THIS ONE

200

Write a balanced equation for the combustion of propane. Calculate the enthalpy for this reaction using your appendix handout.

200

Calculate the heat of a substance when 2.76 kg of the substance (specific heat = 0.562 J/g-K) is heated from 20.5 degrees celsius to 24.5 degrees celsius.

6.20 x 103 J

200

300

How many watts would be measured if a machine produces 1.44 kJ of energy each hour?

0.400 watts

300

Using your balanced equation for propane, calculate the enthalpy of a system when 21.6 g of propane are reacted.

300

Write the equation for the synthesis of Silver Chloride from Silver ions and Chloride ions. Find the change in enthalpy for this reaction.

-65.5 kJ

300

Calculate the initial temperature of a 245 g sample of water that releases 3.55 kJ of heat in order to arrive at a final temperature of 522 K.

525.5 or 525 sig fig

300

400

Calculate the change in internal energy in Joules of a system that releases 4.29 kJ of heat and has 2600 J of work done on it by the system.

-1690

400

Without using a table, predict which has the higher enthalpy:

2 moles of Nitrogen gas at 50 K or 2 moles of Nitrogen gas at 200 K

Higher temp is more endothermic, more positive value

400

Hess's Law on the board

400

Calculate the heat of the reaction, in kJ, when the volume of an aqueous solution is found to be 250 mL and its change in temperature is 27.6 K

-28.9 kJ

400

500

Calculate the change in internal energy of a system that includes 150 g sample of aluminum heated from 20 K to 40 K by absorbing 470 J of heat. Assume the volume does not change.

470 J

500

Write the balanced equation for the synthesis of Silver Chloride from Silver ions and Chloride ions. If the change in enthalpy of this reaction is -65.5 kJ, how much heat would be released given that 14.5 grams of silver chloride was produced?

500

Use your appendix handout to the find the enthalpy for the reaction of solid aluminum with solid iron (III) oxide that produces solid aluminum oxide and solid iron metal

500

Under certain conditions, the heat of combustion of glucose is 15.57 kJ/g. A 2.88 g sample of glucose is burned causing an increase in temperature from 18.5 K to 25.2 K. Find the heat capacity in J/K.

6690 J/K

500