Final
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Chem Equatio ns Lab LR/TY Stoich i- ometry Potpour ri 100 100 100 100 100 200 200 200 200 200 300 300 300 300 300 400 400 400 400 400 500 500 500 500 500 Final
description
Ch 9 SToichioMetry. Final. 100 Chem Eqns How is bromine written in a chemical equation? Answer. Chem Eqns 100. Br 2 It is diatomic. 200 Chem Eqns Write a balanced equation, with phases , for the formation of carbon monoxide from its elements. Answer. Chem Eqns 200. - PowerPoint PPT Presentation
Transcript of Final
ChemEquations
Lab LR/TY Stoichi-ometry
Potpourri
100 100 100 100 100
200 200 200 200 200
300 300 300 300 300
400 400 400 400 400
500 500 500 500 500
Final
100 Chem Eqns
How is bromine written in a chemical equation?
Answer
Chem Eqns 100
Br2
It is diatomic
200 Chem Eqns
Write a balanced equation, with phases, for the formation of carbon monoxide from its
elements.Answer
Chem Eqns 200
2C(s) + O2(g) 2CO(g)
300 Chem Eqns To balance a chemical equation, you may change _______ but you may
not change ______Answer
Chem Eqns 300
To balance a chemical equation, you may change _coefficients_ but may not
change _subscripts or formulas_
400 Chem Eqns
Write a balanced chemical equation for the combustion of heptane, C7H16
AnswerAll Play!!!
Chem Eqns 400 Answer
1C7H16 + 11O2 7CO2 + 8H2O
500 Chem Eqns
Write the balanced equation, with phases, for the reaction between silver nitrate and copper.
Answer All Play!!!!
Chem Eqns 500 Answer
2AgNO3(aq) + Cu(s) 2 Ag(s) + Cu(NO3)2(aq)
100 LabWhat observation allows you to determine that a reactant is the
Limiting Reactant?
Answer
Lab100 Answer
It is gone – used up. It may not always be
possible to observe this, for instance if it is in the
aqueous phase.
200 LabWhat observation allows you to determine that a reactant is the Excess Reactant?
What is the Excess Reactant in most combustions? Explain.
Answer
Lab 200 Answer
• Some of the excess reactant is left over after the reaction stops.
• Oxygen is the ER in combustions b/c it comes from the air and is unlimited.
300 LabExplain why a candle loses mass as it burns.
Answer
Lab 300 Answer
Products are CO2 and H2O gases that escape
into the air during combustion
400 LabIn the AgNO3 Lab, which of the following experimental errors would give a ratio of 1.10 mol Ag/1mol AgNO3?A. Running more than 30 min.B. Insufficient washing/decantingC. Weighing Ag while it is still wet.D. Impure reactantsAnswer All Play!!
Lab 400 Answer
• B and C will increase mass of Aginsufficient washing leaves some copper nitrate in with Ag. Weighing wet gives mass of Ag + water• A does not have an effect b/c the reaction
STOPS when limiting reactant is used up. More time does not give more product after LR is gone.
• D decreases mass of product
500 Lab
What was the purpose of washing and decanting the silver after the
silver nitrate reaction had finished?
Answer
Lab 500 Answer
To purify the Ag by rinsing away the water soluble product, Cu(NO3)2.
100 LR/TY
What is the molar mass, to 2 decimals, of Cu(NO2)2?
Answer
All Play!
LR/TY 100 Answer
155.57 g/mol
200 LR/TY
• Write the mole ratio of phosphorus to fluorine in the following equation
P4 + 6F2 4PF3
Answer
All Play!!!
LR/TY 200
1mole P4 6mol F2
300 LR/TYStoichiometry predicts 2.55 g of Ag product. Data gives the
following: empty beaker = 45.68 g
beaker plus Ag = 47.68 gWhat is % Yield?
Answer
All Play!!!
LR/TY 300 Answer
% Yield = 2.00g x 100 2.55 g
= 78.4%
400 LR/TYList 4 reasons, other than human error, why yield is usually less than 100%.
All Play!!Answer
LR/TY 400 Answer
See your class notes!
500 LR/TYIf 5.00 g of S8 and 10.00 g of Cu are
combined, what is the theoretical yield of product?
16Cu + S8 8Cu2S
AnswerAll Play!!
LR/TY 500 Answer
5.00 g of S8 gives 0.155910 mol Cu2S10.00 g of Cu gives 0.078678 mol Cu2SCu is the Limiting Reactant0.078678 mol Cu2S x 159.17g/mol =
12.52 g Cu2S
100 Stoichiometry
What two types of conversion factors are needed for
stoichiometry calculations?Answer
Stoichiometry 100 Answer
•Mole Ratio from the balanced equation
•Molar Mass
200 Stoichiometry
What part of a balanced equation gives the numerical
part of the mole ratio?Answer
All Play!!
Stoichiometry 200 Answer
Coefficients
300 Stoichiometry
S + 3F2 SF6
What mass of fluorine produces 0.75
moles of SF6?Answer
All Play!!
Stoichiometry 300 Answer
S + 3F2 SF6?g F2 = 0.75 mol SF6 x 3molF2 x 38.00 g F2
1 1mol SF6 1mol F2
= 85.5 ͌ 86 g F2
400 Stoichiometry
S + 3F2 SF6
What mass of sulfur reacts with 3.80 g of Fluorine?
Answer
ALL PLAY!
Stoichiometry 400 AnswerS + 3F2 SF6
?g S = 3.80g F2 x 1mol F2 x 1mol S x 32.07gS1 38.00g F2 3molF2 1mol
S=1.07 g S
S + 3F2 SF6
What is the theoretical yield of SF6 when 3.00 mol of F2 reacts
with excess sulfur? Answer
500 StoichiometryAll Play!!
Stoichiometry 500 AnswerS + 3F2 SF6
? g SF6 = 3.00mol F2 x 1molSF6 x 146.07g SF6
1 3mol F2 1mol SF6
= 146 g SF6
100 Potpourri
A balanced equation has the same number
of ______ on both sides of the arrow.
Answer
Potpourri 100
A balanced equation has the same number of each type of atoms on both sides of
the arrow.
200 Potpourri
The maximum amount of product possible in a chemical
reaction is ________.
Answer
All Play!!
Answers for Potpourri 200
The maximum amount of product possible in a chemical reaction is
theoretical yield.
300 Potpourri
• How many questions must King Arthur and his Knights each answer in order to cross the Bridge of Death and keep from being cast into the Gorge of Eternal Peril?All Play! Answer
Potpourri 300 Answer
Three (3) (III)
400 PotpourriExplain why the product of burning Iron weighs more than the reactant Iron (steel wool)
Answer
Potpourri 400 AnswerOnly one reactant, Fe, is weighed.
O2 cannot be weighed.After reaction, Fe atoms are bonded to Oxygen atoms from
the air, so you are weighing both Fe and O
500 Potpourri
Balance and add phase scripts to the following equation.
Fe2O3 + CO Fe + CO2
AnswerAll Play!!
Potpourri 500 Answer
1Fe2O3(s) + 3CO(g) 2Fe(s) + 3 CO2(g)
Final Jeopardy
Why would a company be interested in the % Yield of its
chemical reactions?Answer
Final Jeopardy Answer
To evaluate cost effectiveness
