Balancing Equations
Is this chemical equation balanced?
N₂(g) + 3H₂(g) —> 2NH₃(g)
Yes
What type of chemical reaction does this model for?
A + BC ---> B + AC
Single-Replacement
What do these symbols mean when you see them in a chemical reaction?
(s), (l), (g)
The state of matter the substance is in.
Solid, liquid, and gas.
What are the number of moles of each substance in this chemical equation?
CH4 + 4Cl2 → CCl4 + 4HCl
Bonus 200 if you can tell me the proper mole ratio for converting from HCl to CH4.
1 mol CH4, 4 mol 4Cl2, 1 mol CCl4, 4 mol HCl
Mole ratio:
1 mol CH4 / 4 mol HCl
What is a precipitate?
A solid produced from a chemical reaction.
Is this chemical equation balanced?
2NO(g) + 3O₂(g) —> 2NO₂(g)
No
What is the model for a decomposition reaction?
AB ---> A + B
What does the symbol (aq) mean in a chemical equation?
Bonus 200 if you can tell me what the triangle symbol means in a chemical equation.
(aq) means dissolved in water or dissolved in an aqueous solution.
The triangle means heat.
How do you write the percent yield mathematical formula?
% yield = actual yield / theoretical yield X 100
Label the chemical reaction on the back of the small board with this work bank:
Subscript, coefficient, reaction arrow, reactants, products
You get one try!
I will reveal the correct answer.
Is this chemical equation balanced?
Cl2 + 2NaBr ---> 2NaCl + Br2
Bonus 200 if you can tell me what type of chemical reaction this is.
Yes
Single-Replacement
What type of chemical reaction does this model for?
Hydrocarbon + Oxygen ---> Carbon Dioxide + Water + heat and light
Combustion
Identify this chemical reaction:
SO₃ + H₂O —> H₂SO₄
Synthesis
What is the percent yield if 14.5 g CaO are actually produced when 15.8 g CaCO3 are heated? Here is your chemical equation: CaCO₃(S) → CaO(s) + CO₂(g).
Identify your actual yield and theoretical yield and then plug them into your percent yield formula to find the answer.
Theoretical Yield = 15.8
% yield = 14.5 / 15.8 x 100
= 91.7%
What is a spectator ion?
An ion that appears on both sides of an equation and is not directly involved in the reaction, it just watches it happen
Balance this chemical equation.
__P4O10 + __H2O ---> __H3PO4
1, 6, 4
Write the model for a synthesis reaction.
A + B ---> AB
Identify this chemical reaction:
Cu + 2AgNO₃ —> 2Ag + Cu(NO₃)₂
Single-Replacement
How many moles of NH₃ are produced when 0.75 mol of nitrogen react with hydrogen?
Here is your balanced chemical equation:
N₂ + 3H₂ —> 2NH₃.
Write down your knowns and unknowns, write your mole ratio, and convert.
Knowns: 0.75 mol N2
Unknowns: ? mol NH3
Mole ratio: 2 NH3 / 1 mol N2
Answer: 1.5 mol NH3
What numbers do you use in a chemical equation to write mole ratios?
Balance this chemical equation.
__Fe₂O₃ + __C —> __Fe + __CO₂
Coefficients:
2, 3, 4, 3
What is the model for a double-replacement reaction?
AB + CD ---> AD + CB
Identify this chemical reaction:
KCN + HBr —> KBr + HCN
Double-Replacement
Perform stoichiometric calculations using mass relationships to determine the number of grams of NH₃ produced when 6.80 g H₂ react with N₂.
The balanced equation is N₂(g) + 3H₂(g) —> 2NH₃(g).
Write your knowns and unknowns, add up your masses, write your mole ratio, and convert. Your steps are: g H₂ → mol H₂ → mol NH₃ → g NH₃.
Knowns:
Mass of hydrogen = 6.80 g H₂
1 mol H₂ = 2.0 g H₂
1 mol NH₃ = 17.0 g NH₃
Unknowns: ? g NH₃
Mole ratio: 2 mol NH3 / 3 mol H2
Answer: 38.53 g NH3
What is the net ionic equation based off of this complete ionic equation?
Pb²⁺(aq) + 2NO₃⁻(aq) + 2K⁺(aq) + 2Cl⁻(aq) —> PbCl₂(s) + 2K⁺(aq) + 2NO₃⁻(aq)
Write this answer on the board. Include all symbols!
Pb²⁺(aq) + 2Cl⁻(aq) —> PbCl₂(s)