Lesson 4: Half equations Flashcards
What do half equations show?
- Half equations show the gain/ loss of electrons for each element involved in a reaction.
What has calcium changed into in this reaction:
Ca + Fe²⁺–> Ca²⁺+ Fe
From Ca –> Ca²⁺
What has happened, in terms of electrons, for Ca to turn into Ca²⁺?
- It has lost 2 electrons.
What is the half equation for Ca —> Ca ²⁺?
Ca –> Ca²⁺ +2e⁻
Where does the electron symbol appear when electrons are lost?
- On the right hand side of the equation.
What has iron changed into in this reaction:
Ca + Fe²⁺–> Ca²⁺+ Fe
-Fe²⁺ –> Fe
What has happened, in terms of electrons, for Fe²⁺ to turn into Fe?
- It has gained 2 electrons.
What is the half equation for Fe²⁺ to Fe?
- Fe²⁺ +2e⁻—> Fe
What is the rule for positive ions to form their neutral atoms?
- Positive ions must gain electrons to form their neutral atoms.
Opposite of what they did to become ion
What is the rule for negative ions to form their neutral atoms?
- Negative ions must lose electrons to form neutral ions.
- Opposite of what they did to become ion*
What are the 2 TopTips when writing half equations?
1.) Balance atoms/ charge
2.) Remember what existis as molecules.
What is the half equation for making water from oxygen?
O₂+4H⁺+4e⁻–> 2H₂O
