Thermochemistry and Stoichiometry

C+ O₂ --> CO₂ + 60kJ, what is the value for ΔH for the reaction?

• +60 J

• -60 kJ/mol

• 12 kJ

• 30 kJ/MOLE

Given the thermochemical equation, calculate the heat evolved when 74.6 g of sulfur dioxide (molar mass = 64.07 g/mol) is converted to sulfur dioxide.

• -115 kJ

• 122 kJ

• -138.39 kJ

• 119.34 kJ

Calculate ΔH when 2 moles of ethanol (C₂H₅OH) reacts with excess oxygen according to the following thermochemical equation?

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O ΔH = −1366.7 kJ

• -2733.4 kJ

• -683.35 kJ

• -1366.7 kJ

• -910.67 kJ

How much heat is evolved from 54.0 g glucose (C₆H₁₂O₆), according to the equation for calculating heat?

• A = .842 kJ

• B= 8.42 kJ

• C= 84.2 kJ

• D 842 kJ

Which of the following is true in an endothermic reaction?

• heat is released; bond forming process

• heat is absorbed; bond breaking process

• heat is released; bond breaking process

• heat is absorbed; bond forming process

Temperature change

• Evidence of a new substance formed from chemical change

• Evidence of release of energy during a chemical change

• Characteristics that can only be observed or measured when atoms of matter rearrange during a chemical change

• Increase or decrease of heat energy in a substance may be evidence of a new substance formed during chemical change

Diagram shows reaction between sodium and water. The reaction is

Is the combustion of gasoline endothermic or exothermic?

• Endothermic
• Exothermic

EXAMPLES OF EXOTHERMIC REACTIONS ,

• Thermal decomposition of carbonate salts

• Neutralization reactions

• Thermal decomposition of nitrate salts

• Dissolving of ammonium or potassium salts in water

A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction.  If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius.  If the reaction is our system, is the system endothermic or exothermic?

• Exothermic
• Endothermic