Preparing to Balance Equations

Preparing to Balance Equations

ISMS Ag Science

​Chemical Reactions

• ​Any change that results in the formation or breaking of chemical bonds

• ​When compounds break down into pieces or pieces come together to form new compounds

Multiple Choice

Which of the following is NOT a chemical reaction?

• 2 H₂O₂ => 2 H₂O + O₂

• 2 Mg + O₂ => 2 MgO

• H₂O + CO₂ + O₂ => CO₂ + H₂O + O₂

• HCl + NaOH => H₂O + NaCl

​The Law of Conservation of Mass

• ​Matter can neither be created or destroyed

• ​Chemical reactions cannot result in a gain or loss or atoms

• ​If an atom is on one side, it's got to be on the other side too

Multiple Choice

According to the Law of Conservation of Mass...

• Matter is gained but not lost in a chemical reaction

• Atoms are sometimes gained but never lost in a chemical reaction

• Matter may be gained or lost in a chemical reaction

• Atoms cannot be gained or lost in a chemical reaction

​Chemical Compounds and Formulas

• Compounds are two or more atoms bonded together

• ​Subscripts = how many atoms of the element there are

• ​Changes in subscripts or element combinations = chemical reaction

Multiple Choice

Which of the following compounds contain TWO (2) Hydrogen atoms?

• 2He

• H₂O

• 2CH₂

• Hg₂H

Multiple Choice

Which of the following contains THREE (3) Sulfur atoms?

• Al₂₍SO₄)₃

• BaS

• B₃(SO₄)₂

• Ca(S₃O₂)₂

​Chemical Compounds and Formulas

• ​Coefficients are numbers placed in front of a chemical formula or symbol

• ​They tell how many of the substance or molecule are involved in the reaction

Multiple Choice

What coefficeient is needed to balance the equation?

N2 + _H₂ -> 2NH₃

• 2

• 6

• 1

• 3

Multiple Choice

Which of the following represents a balanced equation?

• 2N₂ + O₂ -> N₂O

• S₈ + 12O₂ -> 8SO₃

• H₂ + O₂ -> 2H₂O

• H₃PO₄ -> H₄P₂O₇ + H₂O