Chemical Reactions and LCOM

If you start a chemical reaction with 5 atoms of helium, how many atoms will you have after?

• 4 atoms
• 10 atoms
• 1 atom
• 5 atoms

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

• 4Fe + 3O₂ -> 2Fe₂O₃
• 2 Fe + 3O₂ -> Fe₂O₆
• 4 Fe + O₆ -> 2Fe₂O₃
• None of the options are correctly balanced.

Balance this equation...
HgO --> Hg + O₂

• It is balanced 
• 2HgO --> Hg + O₂
• 2HgO --> 2Hg + O₂
• I don't know...Oh well!

Is the following equation balanced or unbalanced?
Fe + S --> FeS

• balanced
• unbalanced

In reactions, products must be equal to..

• Products

• Reactants

• Starters

• Enders

According to the law of conservation of mass, how does the amount of each element on the product side compare to each element on the reactant side?

• The amount of atoms on each side is equal

• The amount of atoms on the product side is greater

• The amount of atoms on the reactant side is greater

• Depends on the reaction

Balance the following chemical equation:

____KClO₃ → ____KCl + ____O₂

• 2KClO₃ → 4KCl + O₂

• 4KClO₃ → 2KCl + 3O₂

• 2KClO₃ → 2KCl + 3O₂

Which reaction type is the following:

C₅H₁₀ + O₂ --> CO₂ + H₂O

• Decomposition

• Synthesis

• Complete Combustion

• Double Replacement

In chemical reactions, what does the principle of conservation of mass mean?

• Matter is not created or destroyed.
• The total mass of the reactants is greater than the total mass of the products.
• The total mass of the reactants is less than the total mass of the products.
• Matter is not changed.
  

Which type of chemical reaction is defined by this equation: AB --> A + B

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement