Laws of Chemical Changes

When 24.3 g magnesium reacts completely with 16.0 g oxygen, exactly 40.3 g magnesium oxide is formed. Which of the following laws is illustrated by this observation?

                                       

 

• Law of Definite Proportion    

• Law of Multiple Proportion          

• Law of Conservation of Mass

• Law of Conservation of Energy

Who formulated the law of multiple proportions?

 

• John Dalton           

• Antoine Lavoisier    

• Joseph Proust

• Democritus

Which of the following pairs of substances illustrate the law of multiple proportions?

• CO and CO₂

• H₂O and D₂O

• NaCl and NaBr

• MgO and Mg(OH)₂

An unbalanced chemical reaction represents a violation of which law?

• The law of conservation of mass

• The law of constant proportions

• The law of multiple proportions

• The law of reciprocal proportions

A water sample from a lake, ocean, rain or pond must have _____ proportions of hydrogen to oxygen.

• identical

• different

• similar

• reciprocal

According to Dalton’s Atomic Theory, matter consists of indivisible _______

• Molecules

• atoms

• ions

• mixtures

Atoms of different elements differ in mass.

• TRUE

• FALSE

What did Dalton’s Theory couldn’t explain?

• gaseous volumes

• conservation of mass

• chemical philosophy

• indivisible atoms

Which of the following may not be explained by Dalton’s atomic theory?

• reason for combining atoms

• conservation of mass

• chemical philosophy

• indivisible atoms

There are no limitations to Dalton’s atomic theory.

• TRUE

• FALSE