Balancing Symbol Equations Flashcards
What is a balanced equation?
An equation where the number of atoms of each element is the same on both sides.
Why must chemical equations be balanced?
The law of conservation of mass states that matter cannot be created or destroyed.
What are state symbols in equations?
(s) solid, (l) liquid, (g) gas, (aq) aqueous.
How do you balance a symbol equation?
Adjust coefficients to ensure equal atoms of each element on both sides.
Balance: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Balance: Fe + O₂ → Fe₂O₃
4Fe + 3O₂ → 2Fe₂O₃
What is the coefficient in an equation?
A number placed before a formula to balance an equation.
Balance: Na + H₂O → NaOH + H₂
2Na + 2H₂O → 2NaOH + H₂
Why can’t you change subscripts when balancing equations?
It would change the chemical identity of the substance.
Balance: C₃H₈ + O₂ → CO₂ + H₂O
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Balance: Al + HCl → AlCl₃ + H₂
2Al + 6HCl → 2AlCl₃ + 3H₂
What is the product of a metal reacting with acid?
A salt and hydrogen gas.
Balance: N₂ + H₂ → NH₃
N₂ + 3H₂ → 2NH₃
What is the reactant in a chemical equation?
The substances that react, on the left side of the equation.
What is the product in a chemical equation?
The substances formed, on the right side of the equation.
Balance: CaCO₃ → CaO + CO₂
Already balanced.
Balance: P + O₂ → P₂O₅
4P + 5O₂ → 2P₂O₅
What is a precipitation reaction?
A reaction where an insoluble solid forms in solution.
Balance: KClO₃ → KCl + O₂
2KClO₃ → 2KCl + 3O₂
What is a combustion reaction?
A reaction where a substance burns in oxygen, producing heat.
Balance: Zn + H₂SO₄ → ZnSO₄ + H₂
Already balanced.
What does a reversible reaction mean?
It can go forward and backward under different conditions.
Balance: Pb(NO₃)₂ → PbO + NO₂ + O₂
2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
Why must mass be conserved in chemical reactions?
Atoms cannot be lost or created, only rearranged.
What does an arrow (→) mean in a chemical equation?
It shows the direction of the reaction.
What is a decomposition reaction?
A reaction where a compound breaks into simpler substances.
What is an exothermic reaction?
A reaction that releases heat energy.
What is an endothermic reaction?
A reaction that absorbs heat energy.
What is a catalyst?
A substance that speeds up a reaction without being consumed.
Balance: H₂O₂ → H₂O + O₂
2H₂O₂ → 2H₂O + O₂
