Balancing Chemical Equations.

Which of the following is an unbalanced equation?

• CaCO ---> CaO + CO2

• PbO2 +2H20 ---> 2Pb + H2O

• 2Na + 2H2O ---> 2NaOH + H2

• CS2 + 2O2 --> CO2 + 2SO2

Balance this equation ... H2 + Cl2 ---> HCl

• it is balanced already

• 3H2 + Cl2 ---> 6H2Cl

• H2 + Cl2 ---> 2HCl

In the equation 2Mg + O2 ---> 2MgO which ones are the reactants?

• Mg and O

• MgO

• Mg and MgO

• O and MgO

B2 + W2 ---> 2BW3 , is this equation balanced?

• yes

• no

• not enough information

When balancing equations, a ______ can be placed to the left of a formula of a substance to make equations balanced.

• charge

• subscript

• any number

• coefficient

Balance this equation. HgO ---> 2HgO + O2

• it is balanced already

• 2HgO ---> Hg + O2

• 2HgO ---> 2Hg + O2

Balance the equation. Sb2S3 + O2 ---> Sb + SO2

• it is balanced already.

• Sb2S3+ 3O2 ---> 2Sb + 3SO2

• Sb2S3 + O2 ---> 2Sb + SO2

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 or lost in a chemical reaction

What is the right side of the chemical equation called in H2+ O2 ---> H2O?

• reactants

• products

• yields

Which equation is balanced?

• 6CO2+ 6H2O ---> C6H12O6 + 6O2

• CO2+ 9H2O ---> C6H12O6+ O2

• CO2+ H2O ---> 3C6H12O6+ O12

• there is no correct answer