CHEMICAL CALCULATION Flashcards
(37 cards)
Based on the following structural formula, calculate the percentage of carbon present:
(CH2CO)2C6H3(COOH).
A. 64.70 % B. 66.67% C. 69.25 % D. 76.73%
A. 64.70 %
A sample of glucose, C6H12O6, contains 4.0E22 atoms of carbon. How many atoms of hydrogen and how many molecules of glucose
does it contain?
A. 8E22 atoms H, 8E22 molecules glucose
B. 4E22 atoms H, 4E22 molecules glucose
C. 8E22 atoms H, 4E22 molecules glucose
D. 8E22 atoms H, 6.7E21 molecules glucose
D. 8E22 atoms H, 6.7E21 molecules glucose
The CO2 that will theoretically be formed when a mixture of 50 g of CH4 and 100 g of O2 is ignited?
A. 34.4 g B. 68.8 g C. 103.1 g D. 137.5 g
B. 68.8 g
At 55oC and 1 atm N2O4 is 50.3% dissociated to NO2 according to the reaction N2O4 2NO2. What is the density of the gas?
A. 1.02 g/L B. 2.27 g/L C. 1.85 g/L D. 1.4 g/L
B. 2.27 g/L
Suppose the reaction Ca3(PO4)2 + 3H2SO4 3CaSO4 + 2H3PO4 is carried out starting with 103 g of Ca3(PO4)2 and 75 g of H2SO4. How
much H3PO4 will be produced? Ca=40; P=31; H=1; O=16; S=32 amu.
A. 74.9 g B. 50.0 g C. 112 g D. 32.5 g
B. 50.0 g
Each day a power plant burns 4E3 tons of coal that contains 1.2 % sulfur by mass. During the combustion process, the sulfur is
completely converted to sulfur dioxide, S + O2 SO2. Calculate the mass of sulfur dioxide produced each day by the plant. S=32u,
O=16u
A. 45 tons B. 69 tons C. 96 tons D. 54 tons
C. 96 tons
The number of cubic feet of gas composed of 28% CO and 72% N2 (by volume) and measured at 85o
F and 100 psia required to reduce 1
ton of ore which is 84% Fe3O4 to metallic ions is:
Fe3O4 + CO 3FeO + CO2
FeO + CO Fe + CO2
A. 4,975.3 B. 5,060.3 C. 5,145.1 D. 5230.0
D. 5230.0
How many pounds of calcium fluoride rock is needed to produce 3000lbs of a 60% HF acid per day if the yield is 90% and the rock
contains 97% pure CaF2?
A. 4105.2 B. 36994.7 C. 3510.0 D. 3.900.0
A. 4105.2
A mixing tank mixes two inlet streams containing salt. The salt concentration in stream 1 is 5% by weight, and in stream 2 it is 15% by
weight. Stream 1 flows at 25 kg/s and stream 2 at 10 kg/s. there is only one exit stream. Find the salt concentration in the exit stream?
A. 5% B. 8% C. 11% D. 13%
B. 8%
Two hundred moles of gaseous mixture CH4 and air contains 50 moles CH4. How many pounds of air are in 1000 lbmoles of the mixture?
A. 750 B. 21,750 C. 25.86 D. 5,172
B. 21,750
Dry air requirement for burning 1 ft3
of CO to CO2 may be around
A. 2.4 ft3 B. 1.75 ft3 C. 0.87 ft3 D. 11.4 ft
A. 2.4 ft3
A furnace is fired with coal containing 6% moisture, 18% VCM, 67% FC, and 9% ash. The refuse analysis shows 5% VCM, 10% M, 23%
FC and 62% ash. The higher heating value of the coal “as fired” is 14,300 BTU/lb. Calculate the percentage of the heating value of the
coal that is lost in the refuse. The moisture in the refuse is due to “wetting down” to prevent dusting. It is not moisture from the original
coal.
A. 4.68% B. 5.75 % C. 9.08% D. 12.92%
A. 4.68%
A Pennsylvania bituminous coal is analyzed as follows: Exactly 2.500 g is weighed into a fused crucible. After drying for 1 h at 110 oC, the
moisture-free residue weighs 2.145 g. the crucible is covered with a vented lid a strongly heated until no volatile matter remains. The
residual coke button weighs 1.528g. The crucible is then heated without the cover until all specks of carbon have disappeared, and the
final ash weighs 0.245g. What is the percent of ash in the coal?
A. 3.4 % B. 35.5 % C. 51.3 % D. 9.8 %
D. 9.8 %
A Pennsylvania bituminous coal is analyzed as follows: Exactly 2.500 g is weighed into a fused crucible. After drying for 1 h at 110 oC, the
moisture-free residue weighs 2.145 g. the crucible is covered with a vented lid a strongly heated until no volatile matter remains. The
residual coke button weighs 1.528g. The crucible is then heated without the cover until all specks of carbon have disappeared, and the
final ash weighs 0.245g. What is the percent of FC in the coal?
A. 51.3 % B. 35.5 % C. 3.4 % D. 9.8 %
A. 51.3 %
Calculate the percentage of carbon present in cadaverine, C5H`14N2, a compound present in rotting meat.
A. 67.4% B. 58.8% C. 51.7% D. 68.2%
B. 58.8%
A sample of vitamin A, C20H30O, contains 4.0E22 atoms carbon. How many atoms of hydrogen and how many molecules of vitamin A
does it contain?
A. 6E22 atoms, 4E22 molecules vitamin A
B. 6E22 atoms, 2E22 molecules vitamin A
C. 4E22 atoms, 4E22 molecules vitamin A
D. 6E22 atoms, 8E22 molecules vitamin A
B. 6E22 atoms, 2E22 molecules vitamin A
Determine the approximate formula weight of Ca(C2H3O2)2
A. 99 B. 69 C. 152 D. 158
D. 158
Determine the empirical formula of a compound that contains 52.9% aluminum and 47.1% oxygen.
A. AlO B. Al2O3 C. Al3O2 D. Al4O6
B. Al2O3
How many moles of CO2 are produced when 3 mol of C2H5OH undergoes complete combustion?
A. 3.00 mol B. 6.00 mol C. 2.00 mol D. 4.00 mol
B. 6.00 mol
If 3 mol of gaseous SO2 react with oxygen to produce sulfur trioxide, how many moles of oxygen are needed?
A. 3.00 mol O2 B. 6.00 mol O2 C. 1.50 mol O2 D. 4.00 mol O2
C. 1.50 mol
How many grams of iron oxide, Fe2O3, can be produced from 2.50 g of oxygen reacting with solid iron?
A. 12.5 g B. 8.32 g C. 2.50 g D. 11.2 g
B. 8.32 g
In making H2O from hydrogen and oxygen, if we start with 4.6 mol of hydrogen and 3.1 mol of oxygen, how may moles of water can be
produced and what remains unreacted?
A. 7.7 mol of water would be produced, with 0.0 mol of O2 remaining
B. 3.1 mol of water would be produced, with 1.5 mol of O2 remaining
C. 2.3 mol of water would be produced, with 1.9 mol of O2 remaining
D. 4.6 mol of water would be produced, with 0.8 mol of O2 remaining
D. 4.6 mol of water would be produced, with 0.8 mol of O2 remaining
What is the charge of manganese in the salt MnF3?
A. 2- B. 1+ C. 1- D. 3+
D. 3+
A common unit of energy is ergs, 1 g-cm2
/s2
. How many ergs are in 1 J?
A. 1 ergs B. 100 ergs C. 1E4 ergs D. 1E7 ergs
D. 1E7 ergs
