Balancing chemical equations

Which problem is balanced?
(Check ALL answers)

• PbO₂ + 2H₂
• SO₂ + H₂0 --> H₂SO₄
• 2Na + 2H₂O --> 2NaOH + H₂

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

Is this balanced?
Al + O₂ → 2Al₂O₃

• Yes
• No

Balance this equation

_Al +_HCl --> _H₂ +_AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5

Is the following equation balanced?
4Fe + 3O₂ --> 2Fe₂O₃

• yes
• no

Is the following reaction balanced?
NaHCO₃ --> Na₂CO₃ + H₂O + CO₂

• yes
• no

What is the left part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical equation

Balance the the following equation.

__Zn+__HCl -->__ZnCl₂ +__H₂

• 1,1,2,1

• 1,1,1,2

• 1,2,1,1

• 2,1,1,1

Determine the coefficients to balance the equation.

__Al +__HCl --> __H₂ +__AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5