Unit 8 Chemical Reactions (HC)

Which of the following is always true about chemical reaction?

• All reactions speed up in the presence of an acid.

• All reactions release toxic gases.

• All reactions rearrange atoms to form new compounds.

• All reactions release energy in the form of light, sound, or heat.

Which of the following is not a chemical change reaction?

• 2 C(s) + O₂ (g) → 2 CO₂ (g)

• 2 Na(s) + Cl₂ (g) → 2 NaCl(s)

• CH₄ (g) + 2 O₂(g) → CO₂ (g) + 2 H₂O (l)

• H₂O(l) → H₂O(g)

Which correctly indicates a dissolved substance?

• H₂O (g)

• Br₂ (l)

• NaCl (aq)

• AgCl (s)

The symbol (s) could refer to:

• a substance that has precipitated out of solution.

• a substance that is soluble.

• a substance dissolved in water

• a substance in the liquid state

Chemical equations must be balanced to satisfy:

• the law of multiple possibilities

• the law of conservation of mass

• the law of conservation of energy

• the law of definite proportions

When the following equation is balanced, the coefficient in front of HCl is:

Al+HCl→AlCl₃ +H₂

• 1

• 2

• 3

• 6

This reaction is an example of a:

Al+HCl→AlCl₃ +H₂

• combustion

• decomposition

• double replacement

• single replacement

• synthesis

The missing coefficients for the following reaction equation are, in order: C₃H₆ + O₂ → CO₂ + H₂O

• 2,8,3,3

• 2,7,6,6

• 2,9,6,6

• 1,6,3,3

The type of reaction below is:

C₃H₆ + O₂ → CO₂ + H₂O

• a. combustion

• b. decomposition

• c. double replacement

• d. single replacement

• e. synthesis

The missing coefficients for the following reaction equation are, in order: P₄ + Cl₂ → PCl₅

• a. 1,1,1

• b. 1,5,2

• c. 2,5,2

• d. 1,10,4