End of Unit 1: Test Review Practice Questions

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

The number in front of a compound or element is a 

• Subscript
• Coefficient
• Superscript
• Charge

The number to the lower side of an element is a 

• Subscript
• Superscript
• Coefficient
• Charge

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit
• Invisible
• Transformed, changed
• None of the above

Which is Chemical Equation is Balanced?

• CH₄+O₂------CO₂+2H₂O
• H₂+O₂-----2H₂O₄
• 4Al+3O₂-----2Al₂O₃

How many nitrogen atoms does NH₃ have?

• 1
• 2
• 3
• 4

Is this equation balanced or unbalanced? 
2Fe₂O₃ + 3C --> 4Fe + 3 CO₂

• balanced
• unbalanced

How many oxygen atoms are in this chemical formula?

• 6 oxygen atoms
• 2 oxygen atoms
• 3 oxygen atoms
• 4 oxygen atoms

Which Chemical Equation is Balanced?

• CH₄+O₂------CO₂+2H₂O
• H₂+O₂-----2H₂O₄
• 4Al+3O₂-----2Al₂O₃