Examen Final química 2do trimestre

Is the following equation balanced or unbalanced?

Fe + S --> FeS

• Balance

• Unbalance

True or False: When balancing chemical equations the subscripts can be change.

• True

• False

Which of the Following Correctly Balances this Equation?

_H₂+_Cl₂ --> _HCl

• 2H₂ + Cl₂ --> 4HCl

• 3H₂ + 3Cl₂ --> HCl

• H₂+Cl₂ --> 2HCl

• H + Cl --> HCl

When balancing equations a ____ can be placed to the left of a formula of a substance to make the equations balanced

• charge

• random number

• subscript

• coefficient

When balancing equations what does

--> mean?

• subscript

• forward

• Just an arrow

• irreversible

Which of the following is an unbalanced equation?

• CaCO₃ --> CaO + CO₂

• 2Na+ 2H₂O-->2NaOH + H₂

• PbO₂ + 2H₂-->2Pb + H₂O

• CS₂ + 2O₂ --> CO₂ + 2SO₂

Which of the following is evidence of a chemical reaction?

• gases forming

• water changing to ice

• boiling water

• paper being cut in half

What coefficient should be used to make the following equation balanced?

N₂+O₂--> _NO

• 1

• 2

• 3

• 4

What is a chemical equation?

• A way to show a physical change using symbols.

• A way to explain a chemical reaction using words

• A short way to show a chemical reaction using symbols

• A way to show a physical change using words.

True or False: Chemical equations use symbols instead of words to summarize chemical reactions.

• False

• True