## Assignment: Enthalpy, Energy, and Temperature Change

Complete the following thermochemistry problems – show all of your work as you set up equations and make calculations.

1. The Travis Scott promotional meal at McDonald’s had $1180$ Calories (note the capital letter- this indicates nutritional Calories). Find the amount of energy in Joules.
2. A $9.00$ g nugget of pure gold absorbed $276$ J of heat. What was the final temperature of the gold if the initial temperature was $25.0$° C? The specific heat of gold is $0.129$ J/(g °C).
3. A sample of silver with a mass of $63.3$ g is heated to a temperature of $384.4$ K and placed in a container of water at $290.0^{\circ}$K. The final (equilibrium) temperature of the silver and water is $292.4^{\circ}$K. What volume of water is in the container? The specific heat of silver is $0.235$ J/(g °C).
4. NSU Chemistry 101L class conducted an experiment in which a measured amount of $\text{NaOH}$ is dissolved in water inside a foam cup calorimeter. A student collected data throughout the experiment. Calculate $\Delta\text{H}$ for the process in kJ/mol.
• Data table from the experiment:
 Mass of NaOH + weigh boat 14.13 g Mass of weigh boat 0.70 g Mass of NaOH Mass of foam cup+water 109.85 g Mass of foam cup 10.25 g Mass of water Initial temp of water 24.5°C Final temp of water 36.8°C Change in temperature (ΔT)
5. You can light a charcoal grill in about a minute. If the grill is prepared using one $20$ pound bag of charcoal (primarily carbon) and two $1$ gallon buckets of liquid oxygen (the density of LOX (liquid oxygen) is $1142$ kg/m3, CRC Handbook of Chemistry and Physics.)
• Write a balanced chemical equation describing this reaction.
• Determine the limiting reagent for this reaction.
• Calculate the mass of each product and any remaining reactant.
• Calculate the amount of heat released by this reaction.
• If this heat is used to warm a $500$ gallon tank of water at $15^{\circ}$C, what is the final temperature?
• If this heat is used to warm $40$ kg of ice at $200^{\circ}$K, what is the final temperature?