Dimensional Analysis
% Comp & Empirical/Molecular Formula
Theoretical Yield
Ionic & Acid/Base Rxns
Random
100
Gold has a density of 19.3 g/cm3. If you have a gold bar with a volume of 44.9cm3, what is its mass?
867g
100
D
100
A chemist performs a synthesis where the calculated theoretical yield of a compound is 55g. After completing the experiment, they isolate 44.0g of the product. What is the percent yield?
80%
100
Balance the following rxn and label the acid and base:
HF + Ba(OH)2 --> H2O + BaF2
2HF + Ba(OH)2 --> 2H2O + BaF2
acid base
100
Argon has three naturally occurring isotopes: argon-36, argon-38, and argon-40. Based on argon’s reported atomic mass, which isotope exist as the most abundant in nature? Explain
Argon has an atomic mass of 39.948 amu, which is closet to argon-40, suggesting that it is the most abundant isotope
200
Wild fresh Coho salmon fillets are on sale at Sprouts for $9.99 per pound. What is the cost in dollars of 2.50 kg of fillets?
$55.1
200
Determine the empirical formula of a compound containing 83% potassium and 17.0% oxygen.
K2O
200
How many moles of water can we make from 6 moles of hydrogen and 4 moles of oxygen?
2 H2(g) + O2(g) → 2H2O(g)
6 mol H2O
200
Write the following rxn, balance it and determine if the compounds are soluble:
aqueous potassium sulfate is mixed with aqueous barium bromide
K2SO4 (aq) + BaBr2 (aq) -->2KBr(aq) + BaSO4 (s)
200
300
At a given point in its orbit, the moon is 2.4x105 miles from earth. How long does it take light from a source on earth to reach a reflector on the moon and then return to earth? (Speed of light = 3.0x108 m/s)
2.6 sec
300
A covalent compound has an empirical formula of HO. The compound’s molecular mass is determined to be 34.01 amu. What is this compounds molecular formula?
H2O2
300
What volume, in liters, of 0.150 M BaCl2 solution is needed to react completely with 0.200 L of a 0.450 M AgC2H3O2 solution according to the equation:
BaCl2(aq) + 2AgC2H3O2(aq) → Ba(C2H3O2)2(aq) + 2AgCl(s)
0.3 L
300
Finish the following rxn, balance it, and indicate the conjugate acid & conjugate base
H2CO3 +Sr(OH)2 -->
H2CO3 + Sr(OH)2 --> SrCO3 + 2H2O
conj. base conj. acid
300
Convert 2800L into in3
1.7x105 in3
400
A dentist has 5.0×102 gal of nitrous oxide on hand. If the flow rate of the gas is 5.5 L/min and the average procedure takes 25 minutes, how many procedures can the dentist perform before he runs out of laughing gas?
14 procedures
400
Lactic acid, C3H6O3, is formed in muscle cells during heavy exertion. Determine its percent composition.
𝟑𝟗.𝟗𝟗 %𝐂
𝟔.𝟕𝟑 %𝐇
𝟓𝟑.𝟐𝟖 %𝐎
400
Calculate the maximum number of grams of NH3 that can be produced by the reaction of 2.00 g of N2 with 3.00 g H2. Also determine the percent yield if the experiment yields 2.17g of NH3.
N2(g) + 3 H2(g) → 2 NH3(g)
LR = N2
Theoretical yield =2.43g
Percent Yield = 89.3%
400
Write the balanced full chemical equation, complete ionic equation, and net ionic equation for the reaction between calcium sulfide and ammonium phosphate. Be sure to include physical states.
Full:
3CaS(aq) + 2(NH4)3PO4(aq) → Ca3(PO4)2(s) + 3(NH4)2S(aq)
Complete Ionic:
3Ca2+(aq) + 3S2−(aq) + 6NH4+(aq) + 2PO43−(aq) → Ca3(PO4)2(s) + 6NH4+(aq) + 3S2−(aq)
Net Ionic:
3Ca2+(aq) + 2PO43−(aq) → Ca3(PO4)2(s)
400
Rubidium has two known isotopes with masses 84.9117 amu and 86.9092 amu (27.8 % abundance). If the weighted average atomic mass is 85.4678 amu, what is the percentage abundance for the lower mass isotope? Show all work for credit.
72.2%
500
You are working at a fast food restaurant and each hour you wrap 184 hamburgers. You work 8 hours per day. You work 5 days a week. You get paid every 2 weeks with a salary of $840.34. How many hamburgers will you have to wrap to make your first one million dollars? (round to 3 sig figs)
1.75x107 burgers
500
A major textile dye manufacturer developed a new yellow dye. The dye has a percent composition of 75.95% C, 17.72% N, and 6.33% H by mass with a molar mass of about 240 g/mol. Determine the molecular formula of the dye.
C15H15N3
500
When iron metal is heated with oxygen gas it produces solid iron(III) oxide. If 50.0 g of iron are reacted with 25.0 g of oxygen, what is the theoretical yield of iron(III) oxide in grams?
When running this experiment in the lab, 49.7 g of iron(III) oxide was produced. What was the percent yield?
Balanced Eq = 4Fe(s) + 3O2(g) → 2Fe2O3(s)
Theoretical Yield = 71.5g
Percent Yield = 69.5%
500
Write the balanced full chemical equation, complete ionic equation, and net ionic equation for the reaction between molybdenum(V) iodide and potassium carbonate. Be sure to include physical states.
Full chemical eq: 2MoI5(aq) + 5K2CO3(aq) → Mo2(CO3)5(s) + 10KI(aq)
Complete Ionic:
2Mo5+(aq) + 10I−(aq) + 10K+(aq) + 5CO32−(aq) →
Mo2(CO3)5(s) + 10K+(aq) + 10I−(aq)
Net Ionic: 2Mo5+(aq) + 5CO32−(aq) → Mo2(CO3)5(s)
500
A rocket ship was powered by a propellant made of hydrazine, N2H4, combined with an oxidizer, N2O4, that reacted according to the following equation:
2N2H4(l) + N2O4(l) → 3N2(g) + 4H2O(g) ΔHrxn = −1049 kJ
The average mass of propellant for the rocket ship was 5,187 lb. Assuming it was a 50:50 mixture, what’s the maximum amount of heat it could produce?
1.341×107 kJ of heat produced