Midterm 2 (THERMOCHEMISTRY) Review

Energy

100

PCl5(g) → PCl3(g) + Cl2(g)| P4(s) + 6Cl2(g) → 4PCl3(g) ΔH = -2439 kJ | 4PCl5(g) → P4(s) + 10Cl 2(g) ΔH = 3438 kJ |

What is 249.8 kJ

200

2CO2(g) + H2O(g) → C 2H2(g) + 5/2O2(g)| C2H2(g) + 2H2(g) → C2H6(g) ΔH =-94.5 kJ | H2O(g) → H2(g) + 1/2O2 (g) ΔH =71.2 kJ | C2H6(g) + 7/2O2(g) → 2CO2(g) + 3H2O(g) ΔH =-283 kJ|

What is 235 kJ

300

N2H4(l) + H2(g) → 2NH3(g)| N2H4(l) + CH4O(l) → CH2O(g) + N2(g) + 3H2 (g) ΔH = -37 kJ | N2(g) + 3H2(g) → 2NH 3(g) ΔH = -46 kJ | CH4O(l) → CH2O(g) + H 2(g) ΔH = -65 kJ|

What is -18 kJ

400

H2SO4(l) → SO3(g) + H2O(g)| H2S(g) + 2O2(g) → H2SO4(l) ΔH = -235.5 kJ | H2S(g) + 2O2(g) → SO 3(g) + H2O(l) ΔH = -207 kJ | H2O(l) → H2O(g) ΔH = 44 kJ |

What is 72 kJ

500

1/2H2(g) + 1/2Cl2(g) → HCl(g)| COCl2(g) + H2O(l) → CH2Cl2(l) + O2(g) ΔH = 47.5 kJ | 2HCl(g) + 1/2O2(g) → H 2 O(l) + Cl2(g) ΔH = 105 kJ | CH2Cl2(l) + H2(g) + 3/2O 2(g) → COCl2(g) + 2H 2O(l) ΔH = -402.5 kJ|

What is -230 kJ

THEORY

100

The value of the ΔH for any reaction that can be written in steps equals the _____of the value of ΔH for each of the individual steps

What is sum

200

When an equation is reversed- the sign of ΔH must also be _________________.

What is reversed

300

If all coefficients of an equation are multiplied or divided by the same factor, the value of ΔH must likewise be ______________________.

What is multiplied or divided by the same factor

400

The molar enthalpy of fusion, ΔHfus, and the molar enthalpy of vaporisation, ΔHvap, of a substance are 1.3664 kJ mol-1 and 16.32 kJ mol-1, respectively. What is the molar enthalpy of sublimation, ΔHsub of that substance in kJ mol-1?

What is 17.6864 kJ mol-1

500

The enthalpy change of a physical or chemical process depends only on the beginning conditions (reactants) and end conditions (products). The enthalpy change is __________of the pathway of the process and the number of intermediate steps in the process

What is independent

WHAT IS MISSING

100

2C2H4O(l) + 2H2O(l) → 2C2H6O(l) + O2(g)| C2H6O(l) + 3O2(g) → 2CO2(g) + 3H2O(l) ΔH = -685.5 kJ | C2H4O(l) + 5/2O2(g) → 2CO2(g) + 2H2O(l) ΔH =_________| answer = 204.0 kJ|

What is -583.5 kJ

200

N2(g) + 2O2(g) → 2NO 2(g)| N2(g) + 3H2(g) → 2NH3(g) ΔH = -115 kJ | 2NH3(g) + 4H2O(l) → 2NO2(g) + 7H2(g) ΔH = -142.5 kJ | ________→ H2(g) + 1/2O 2(g) ΔH = -43.7 kJ

What is H2O(l)

300

CO2(g) → C(s) + O2(g)| H2O(l) → H2(g) + 1/2O2(g) ΔH = 643 kJ | C2H6(g) → _______________ ΔH = 190.6 kJ | 2CO2(g) + 3H2O(l) → C2H6(g) + 7/2O2(g) ΔH= 3511.1 kJ|

What is 2C(s) + 3H2(g)

400

N2H4(l) + CH4O(l) → CH2O(g) + N2(g) + 3H2 (g)| 2NH3(g) → N2H4(l) + H2(g) ΔH = 22.5 kJ | 2NH3(g) → N2(g) + 3H 2(g) ΔH = 57.5 kJ | _________________________ ΔH = 81.2 kJ |

What is CH2O(g) + H2(g) → CH 4O(l)

500

HCl(g) + NaNO2(s) → HNO2(l) + NaCl(s)| 2NaCl(s) + H2O(l) → 2HCl(g) + Na2O(s) ΔH = 507 kJ| NO(g) + NO2(g) + Na2O(s) → 2NaNO2(s) ΔH = -427 kJ| NO(g) + NO2(g) → N2O(g) + O2(g) ΔH = -43 kJ| ______________________________ ΔH = 34 kJ |

What is 2HNO2(l) → N2O(g) + O2(g) + H 2O(l)

HEAT TRANSFER AND ENTHALPY CHANGE

100

Is ΔH positive or negative in an exothermic reaction?

What is negative.

200

How much heat energy is obtained when 1 kg of ethane gas, C2H6 (molar mass: 30.07 g/mol), is burned in oxygen according to the equation: 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l) ΔHm = –3120 kJ mol–1 Write the thermochemical equation with energy terms.

What is 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)+ 51 879 kJ

300

In an endothermic reaction, is heat gained or lost in the system? Draw a diagram to illustrate the transfer of energy in an exothermic reaction.

What is gained, reactants--> products

400

A sample of ethanol absorbs 23.4kJ of energy. The temperature increases from 5.6 degrees Celsius to 19.8 degrees Celsius. What is the mass of the sample if the specific heat capacity of ethanol is 2.46 J/ (goC)?

What is 669.87 grams

500

H2SO4(aq) + 2NaOH(aq) --> Na2SO4 (aq) + 2H2O (l) + 114 kJ (a)What is the enthalpy change for this reaction? (b)Write this thermochemical equation, using the deltaHx to produce H2O (g) notation (c) Calculate the molar enthalpy of neutralization in kJ/mol sulfuric acid (d) Draw the potential energy diagram for the reaction

What is (c) -114 kJ/mol H2SO4 (d) -57 kJ/mol NaOH

CALORIMETRY

100

C + O2 ? CO2 + 388.8 kJ a) What quantity of heat will be released when 3.0 g of carbon burns? **carbon has a molar mass of 12.01 g/mol

What is 97.2 kJ will be released

200

50.0mL of 0.10 mol/L at 23.5 degrees C is added to 50.0mL of 0.10 mol/L NaOH. The temperature rises to 30.1 degrees Celsius. What is the molar enthalpy of neutralization for HCl in this reaction?

What is -551 760 J/ mol or -552 kJ/mol

300

A 1 mol sample of acetic acid, CH3CO2H, was burned in oxygen in a calorimeter. The calorimeter contained 925 g of water and had a heat capacity of 2.53 kJ/ degree C. The temperature of the calorimeter and its contents increased from 22.2 degrees C to 26.5 degrees C. What is the molar heat of combustion of acetic acid?

What is -27 504 J/ mol or -27.5 kJ/ mol

400

A 3.5 g sample of quinine, C6H4O2 (108.09 g/mol), was burned in a calorimeter with a heat capacity of 3.43 kJ/ degree Celsius and contained 1.2 kg of water. The temperature of the calorimeter and water increased from 19.0 degrees Celsius to 28.0 degrees Celsius.

What is -2350 kJ/mol

500

A 2.56 g sample of anthracene, C4H10 (58.12 g/ mol), was burned in a calorimeter with a heat capacity of 0.428 kJ/ degrees Celsius. The calorimeter was immersed in 1500 mL of water. If the molar heat of combustion of anthracene is -2400 kJ/mol, what would the final temperature of the water and calorimeter be if the initial temperature is 22.4 degrees Celsius?

What is 38.2 degrees celsius