Chemical Reactions Quiz

What is the frequency of occurrence of various elements in an equation called?

• molecular weight

• reaction rate

• atomic number

• f-number

Which element should be balanced first if two or more elements have the same frequency number?

• Non-metallic element

• Metallic element

• Element with lowest atomic number

• Element with highest mass

In balancing equations, which metallic element should be balanced first if they have the same frequency number?

• The one with the lowest atomic number

• The one with the highest mass

• The one with the highest atomic number

• The one that appears first in the equation

What type of reaction is defined as a reaction where two or more elements or compounds combine to form a single compound?

• Decomposition reaction

• Displacement reaction

• Combination reaction

• Synthesis reaction

What is a synthetic reaction?

• A reaction that involves only non-metals

• A reaction where a compound breaks down

• A reaction where two elements combine to form a new compound

• A reaction that occurs in the presence of heat

What is the process called when a compound breaks down into simpler substances?

• Combination reaction

• Decomposition reaction

• Synthesis reaction

• Thermal reaction

What type of decomposition reaction is brought about by heat?

• Chemical decomposition

• Photolytic decomposition

• Thermal decomposition

• Electrolytic decomposition

In the equation 2HgO → 2Hg + O₂, what type of reaction is occurring?

• Single displacement reaction

• Combination reaction

• Decomposition reaction

• Synthesis reaction

Which of the following is an example of a combination reaction?

• NaCl → Na + Cl₂

• 2H₂O → 2H₂ + O₂

• PbS + O₂ → PbSO₄

• 2Mg + O₂ → 2MgO

What should be the order of balancing non-metallic elements with the same frequency number?

• In decreasing order of atomic numbers

• In increasing order of atomic numbers

• In alphabetical order

• In random order