Exothermic and endothermic reactions

Exothermic and endothermic reactions

by Miss Gu

Multiple Choice

1. Equal amounts of four different substances (A-D) where added separately to equal amounts of an acid and a thermometer placed in the mixture. For which substance is the reaction the most exothermic?

• A. temperature rises by 3 $$\degree C$$    

• B. temperature falls by 5 $$\degree C$$   

• C. temperature falls by 3 $$\degree C$$    

• D. temperature rises by 5 $$\degree C$$  

Multiple Choice

2. The breaking of bonds in a chlorine molecule must be?

• A. endothermic  

• B. equilibrium   

• C. electrolytic  

• D.  exothermic

Multiple Choice

 3. Which of the following is a chemical change?

• A. melting an ice-cube  

• B. lighting a match  

• C. cooling a cup of tea                    

• D. dissolving sugar in coffee

Multiple Choice

4. Equal amounts of four different substances (A-D) where added separately to equal amounts of an acid and a thermometer placed in the mixture. For which substance is the reaction the least endothermic?

• A. temperature falls by 3 $$\degree C$$    

• B. temperature rises by 5 $$\degree C$$

• C. temperature falls by 5 $$\degree C$$

• D. temperature rises by 3 $$\degree C$$

Multiple Choice

5. When ammonium chloride dissolves in water the temperature falls. The type of energy change is described as?

• A. exothermic    

•  B. activated  

• C. decomposition            

• D. endothermic

Multiple Choice

6. Which of these processes is always exothermic?

• A. evaporation

• B. burning

• C. insulation

• D. melting

Multiple Choice

7. When an exothermic reaction takes place, the reaction mixture gets hotter because?

• A.    more energy is released when new bonds are formed than is taken in when existing bonds in the reactants are broken

• B.    exothermic changes always produce gases

• C.    energy is always released in a chemical change which makes new substances

• D.    in an exothermic change the products are more stable than the reactants

Multiple Choice

8. When an endothermic reaction takes place, the reaction mixture takes in heat because?

• A.   in an endothermic change the products are less stable than the reactants

• B.   less energy is released when new bonds are formed than is taken in when existing bonds in the reactants are broken

• C.   energy is always absorbed in a chemical change which makes new substances

• D.   endothermic changes always produce energy

Multiple Choice

9. The chemical change when a fuel burns can be described as?

• A.      a precipitation

• B.     a reversible reaction

• C.      an endothermic reaction

• D.      an exothermic reaction

Multiple Choice

10.  Change 1. When calcium carbonate forms calcium oxide and carbon dioxide heat is absorbed.       

Change 2. Calcium oxide releases heat when shaken with carbon dioxide.

Which line BEST describes these changes?

• A.   change 1 is exothermic; change 2 is endothermic

• B.   change 1 is endothermic; change 2 is exothermic  

• C.   change 1 is endothermic; change 2 is endothermic

• D.   change 1 is exothermic; change 2 is   exothermic