Thermo Chemistry review

A student performed an experiment based on the chemical reaction below:

CH3CO2H + NaHCO3 → CH3CO2Na

The student recorded the following data:

In her report, which conclusion would be correct?

• The products had a higher energy than the reactants, which represents an endothermic reaction.

• The reactants had a higher energy than the products, which represents an exothermic reaction

• The products had a higher energy than the reactants, which represents an exothermic reaction.

• The reactants had a higher energy than the products, which represents an endothermic reaction.

 In an exothermic reaction, the energy stored in the chemical bonds of the reactants is ​ (a)   the energy stored in the bonds of the products. 

• greater than
• less than
• equal to

What energy is found in chemical bonds holding gasoline molecules together?

• Mechanical energy

• Electrical energy

• Chemical energy

• Solar energy

Many chemical reactions occur within the human body. One common reaction is the catabolism of one glucose molecule, which produces about 36 ATP molecules. This accounts for only 40% of the energy released by the exothermic reaction. What happens to the energy not converted to ATP?

• It is converted back to glucose.

• It is lost as heat.

• It is used to make molecules of ADP.

• It is stored in the body as fat.

A sample of a compound is added to distilled water in a clean beaker. A reaction occurs, and the water temperature drops rapidly. Which of the following statements is best supported by this observation?

• An endothermic reaction occurred.

• A dehydration reaction occurred.

• The water was originally warmer than the compound.

• The beaker was contaminated by another compound.

The average kinetic energy of an object can be measured by its -

• Density

• Temperature

• Mass

• Magnetism

The statement that energy cannot be created or destroyed is part of the law of ___________ ____ __________ (3 words).

(Answer is 3 words, all lowercase).

Represented below are two student sketches from a lab report. Each sketch shows a graphical analysis of a chemical reaction observed during the lab.

diagram A is ​ ​ (a)   and diagram B is ​ (b)  

• exothermic
• endothermic

On a sunny summer day, why does the pool feel cooler than the concrete around it?

• The water has a lower specific heat than the concrete.

• The concrete has absorbed as much energy as the water.

• The water is transferring as much heat as the concrete.

• The concrete has a lower specific heat capacity than the water.

The graph below shows the energy changes of a chemical reaction.

Which of the following reaction(s) represent(s) the graph above?

• 110 kJ + 2N2O5(g) → 4NO2(g) + O2(g)

• Mn(s) + 2HCl(aq) → MnCl2(aq) + H2(g) + 221 kJ

• P4O10(g) +6H2O(l) → 4H3PO4(aq) + 424 kJ