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What is a compound

• sodium

• sugar

• nitrogen

• air

This is a chemical reaction for the decomposition of carbonic acid into water and carbon dioxide.

How does this reaction support the Law of Conservation of Mass?

• Several molecules of water are produced.

• The mass of carbon atoms is reduced during the reaction.

• The mass of the atoms in the reactant equals the mass of the atoms in the products.

• The mass of hydrogen atoms is the only thing that remains the same before and after the reaction.

Which is classified as an element?

• carbon dioxide

• iron

• vinegar

• water

Which is the best example of a chemical change?

• butter melting

• egg cooking

• paper tearing

• water evaporating

Which chemical equation best represents the Law of Conservation of Mass?

•  $H\ +\ O\ \rightarrow\ H_2O$  
  

•  $H_2\ +\ O_2\ \rightarrow\ H_2O$  

•  $2H_2\ +\ O_2\ \rightarrow\ 2H_2O$  

•  $H_2\ +\ O_2\ \rightarrow\ 2H_2O_2$