9 Chemical Bonding: Balancing Equations

Which side of a chemical equation is the product side?

• Left (before the yields sign)
• Right (after the yields sign)

How many atoms of aluminum are on each side of the following equation: 4Al + 3O₂ --> 2Al₂ O₃

• 2
• 6
• 1
• 4

Tags

NGSS.HS-PS1-7

Finish a blalanced equation:
Mg(OH)₂ --> __________

• Mg(OH)₂ --> MgOH
• Mg(OH)₂ --> MgO+ H₂O
  
• Mg(OH)₂ --> MgO+ H₂
• Mg(OH)₂ --> Mg+ H₂O

At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?

• the product is doubled
• the product is half the mass of the reactants
• the mass is the same
• the mass changes depending on the reaction

Tags

NGSS.HS-PS1-7

Balance this equation,            
Al₂O₃ --> Al + O₂ 

• Cannot be balanced
• 2Al₂O₃ --> 2Al+3O₂ 
• 2Al₂O₃--> 4Al+3O₂ 
• 3Al₂O₃--> 2Al+O₂ 

Tags

NGSS.HS-PS1-7

Which elements are(is) not balanced?
LiNO₃ +CaBr₂ --> Ca(NO₃)₂ +  LiBr   

• Li
• Ca and Li
• O and N
• Ca

Balance the equation:
Si(OH)₄+NaBr--> SiBr₄+NaOH

• Si(OH)₄+2NaBr--> SiBr₄+NaOH
• Si(OH)₄+4NaBr--> SiBr₄+4NaOH
• Si(OH)₄+NaBr--> SiBr₄+4NaOH
• Si(OH)₄+2NaBr--> SiBr₄+2NaOH

N₂ + H₂ = NH₄

• Balanced
• Unbalanced

Tags

NGSS.HS-PS1-7

What does the Law of Conservation of Mass state?

• Matter cannot be gained or lost in a chemical reaction.
• Matter can only be lost in a chemical reaction.
• Matter can only be gained in a chemical reaction.
• Matter can be gained and lost in a chemical reaction. 

Tags

NGSS.HS-PS1-7

Which of the following is NOT true of oxidation states?

• metals tend to give up electrons having positive oxidation states

• nonmetals tend to take electrons having negative oxidation states

• a common oxidation state for halogens is -1

• a common oxidation state for metals in group 13 is -3