Exam 9: Thermochemistry: Chemical Energy

How much heat is absorbed when 30.00 g of C(s)reacts in the presence of excess SO₂(g)to produce CS₂(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO₂(g)→ CS₂(l)+ 4 CO(g)ΔH° = 239.9 kJ

A process is carried out at constant pressure.Given that 0 > ΔH > ΔE,

He gas is contained in a one-liter flask that is connected to an empty one-liter flask with a closed stopcock between the two flasks.When the stopcock is opened some of the He enters the evacuated flask.For this system

-What are the signs of ΔH and ΔS for the reaction represented in the above drawing?

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below.When 0.015 mol of Na is added to 100.00 g of water,the temperature of the resulting solution rises from 25.00°C to 31.45°C.If the specific heat of the solution is 4.18 J/(g ∙ °C),calculate ΔH for the reaction,as written. 2 Na(s)+ 2 H₂O(l)→ 2 NaOH(aq)+ H₂(g)ΔH = ?

Which is a measure of the sum of the kinetic and potential energies of each particle in the system?

It takes 15.5 kJ of energy to raise the temperature of 200 g of benzene from 25.0°C to 70.0°C.What is the specific heat of benzene?

Is a hydroelectric dam a form of kinetic or potential molecular energy?

When 50.0 mL of 0.400 M Ca(NO₃)₂ is added to 50.0 mL of 0.800 M NaF,CaF₂ precipitates,as shown in the net ionic equation below.The initial temperature of both solutions is 25.00°C.Assuming that the reaction goes to completion,and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ∙ °C),calculate the final temperature of the solution. Ca²⁺(aq)+ 2 F^-(aq)→ CaF₂(s)ΔH° = -11.5 kJ

At a constant pressure of 2.50 atm what is the enthalpy change ΔH for a reaction where the internal energy change ΔE is 58.0 kJ and the volume increase is 12.6 L? (1 L·atm = 101.325 J. )