Unit 6 Review

Balance this equation,            Al₂O₃ ---> Al + O₂ 

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

How many Al atoms are in this compound?         4Al₂O₃

• 2
• 8
• 6
• 4

A chemical reaction that produces energy is a /an

• endothermic reaction
• exothermic reaction 
• energy
• chemical reaction 

A chemical reaction that requires energy is a

• exothermic reaction 
• endothermic reaction 
• over reaction 

Salt dissolved in water is an example of:

• colloid
• solution
• element

A combination of substances that are not chemically combined is called a(n)____________. 

• mixture
• compound
• physical

Located on the left side of the reaction

• reactants
• products

Is sour milk a chemical or physical change?

• chemical
• physical

Is burning toast a chemical or physical change?

• physical
• chemical

Is spoiled meat a chemical or physical change?

• chemical
• physical