Name ______Date ______Period ______
Ch 6: Chemical Reactions
60 pts.
1. A substance that undergoes a change in a chemical reaction is
a. a product.
b. a chemical.
c. a reactant.
d. an enzyme.
2. In an exothermic reaction, energy is transferred from
a. the reactant(s) to the surroundings.
b. the surroundings to the reactants.
c. one reactant to another.
d. the container to the chemicals
3. A synthesis reaction is a reaction between at least two elements in which
a. one breaks down into at least two products.
b. a compound is decomposed by an electric current.
c. a compound burns in the presence of oxygen.
d. a new more complex compound is formed.
4. A chemical equation is balanced by changing or adding
a. chemical symbols.
b. subscripts
c. coefficients.
d. reactants.
5. What happens in a chemical reaction?
a. atoms are destroyed.
b. atoms are created.
c. atoms are heated and cooled.
d. atoms are rearranged.
6. Which of the following is an example of a decomposition reaction?
a. photosynthesis
b. digestion
c. respiration
d. exchange of ions between two compounds.
7. When methane (CH4) is burned in the presence of oxygen (O2), the two chemicals react together in a process called combustion.
Which of these compounds could be a possible product of this combustion reaction?
a. NH3
b. SO2
c. H2O
d. CS2
8. Which statement about endothermic reactions is correct?
a. energy is always created in the form of heat.
b. energy is transferred from the surroundings to the reactants.
c. energy is used to force electrons to move to higher energy levels.
d. energy is transferred from the reactants to the surroundings.
9. Which of the following represents the word equation
Magnesium + oxygen à magnesium oxide?
a. CH4 + O2 à CH4O2
b. MgO + O à MgO2
c. 2Mg + O2 à 2MgO
d. 2CH4 + O2 à 2CH3OH
10. Find the number of neutrons in Oxygen 18.
a. 2
b. 8
c. 10
d. 18
11. Which element does the shell model represent?
A. C.
B. D.
12. A student is testing the conductivity of two solid substances. Substance A has high conductivity and substance B has low conductivity.
Based on this information, what must be true regarding these two substances?
a. Electrons in substance A are able to move more easily than electrons in substance B.
b. There is more energy stored in chemical bonds in substance A than there is in substance B.
c. The atomic nuclei in substance A have more mass than the atomic nuclei in substance B.
d. Substance A contains a higher percentage of radioactive atoms than does substance B.
Short answers & Extended responses:
13. Define Endothermic and Exothermic reactions. Give an example of each. (4 pts.)
14. Balance the following equation and state the type of reaction. Show the element inventory (4 pts.)
______Zn + ______AgCl à ______ZnCl2 + ______Ag
15. Balance the following equation and state the type of reaction. Show the element inventory (4 pts.)
______Fe + ______O2 à ______Fe2O3
16. Label the chemical equation below using vocabulary terms (2 points each).
______
2Mg + O2 à 2MgO
______
17. Graphing(4 pts.)
a. What is the dependent variable
b. What is the independent variable
c. What is happening to the temperature at the “ice melting” position
d. What states of matter is located at the “water boils” position