Q&A Hero

Q: A 3.075 g sample of a compound containing only carbon, hydrogen, and oxygen is burned in an excess of dioxygen, producing 6.990 g CO2 and 2.862 g H2O. What mass of oxygen is contained in the original sample? A) 0.8472 g B) 1.167 g C) 3.915 g D) 4.129 g E) 0.2134 g

Q: A compound containing only carbon, hydrogen, and oxygen is subjected to elemental analysis. Upon complete combustion, a 0.1804-g sample of the compound produced 0.3051g of CO2and 0.1249 g of H2O. What is the empirical formula of the compound? A) C3H6O3 B) C3H3O C) C4H8O3 D) C2H2O E) CH2O3

Q: The amount of calcium in a 15.0-g sample was determined by converting the calcium to calcium oxalate, CaC2O4. The CaC2O4weighed 12.6g. What is the percent of calcium in the original sample? A) 10.8 % B) 26.3 % C) 14.8 % D) 33.7 % E) 84.0 %

Q: Which of the following contains the greatest mass of bromine atoms? A) 11.0 g of KBr B) 23.0 g of Br2 C) 0.076 mol of KBr D) 0.092 mol of Br2 E) 32.0 g of NaBrO3

Q: NaHCO3is the active ingredient in baking soda. How many grams of oxygen are present in 0.67g of NaHCO3?A) 0.024 gB) 0.128 gC) 7.98 x103gD) 0.043 gE) 0.38 g

Q: How many grams of potassium are present in 21.6g of K2Cr2O7? A) 5.74 g B) 1.105 g C) 2.87 g D) 78.2 g E) 10.8 g

Q: How many grams of hydrogen atoms are present in 18.4g of water? A) 37.1 g B) 1.02 g C) 2.06 g D) 1.96 g E) 12.3 g

Q: A crystal of the mineral troegerite, (UO2)3(AsO4)2+ 12H2O (FM = 1304 amu), contains ____% arsenic by mass.A) 15.4B) 39.8C) 61.0D) 26.4E) 11.5

Q: What is the percentage by mass of hydrogen in ammonium phosphate, (NH4)3PO4? A) 8.11 % B) 4.06 % C) 52.0 % D) 40.0 % E) 3.00 %

Q: What is the mass percentage of carbon in the compound C6H6O2? A) 5.5 % B) 70.9 % C) 65.5 % D) 29.1 % E) 14.3 %

Q: Which of the following compounds has the same percentage of carbon and hydrogen by mass as cyclohexane, C6H12? A) C6H14, hexane B) C5H10, pentene C) C6H10, cyclohexene D) C6H6, benzene E) C6H12O6, glucose

Q: Which of the following compounds has the highest percentage of nitrogen by mass? A) (NH4)2SO3 B) NaNO3 C) N2Cl4 D) NH4NO2 E) HNO3

Q: Which of the following compounds has the highest percentage of hydrogen atoms by mass? A) CH3COOH B) C2H5OH C) CH3OH D) H2CO3 E) H2C2O4

Q: The mineral leadhillite, which is essentially Pb4(SO4)(CO3)2(OH)2(FW = 1079 g/mol), contains ____% hydrogen by mass. A) 76.81 B) 0.1868 C) 2.226 D) 17.79 E) 2.972

Q: What is the percentage by mass of hydrogen in the insecticide Lindane, C6H6Cl6? A) 20.0 % B) 1.20 % C) 47.2 % D) 8.80 % E) 2.08 %

Q: What is the percent by mass oxygen in (NH4)2SO3? A) 41.3 % B) 20.7 % C) 54.0 % D) 42.0 % E) 1.00 %

Q: An ore sample with a mass of 68.0 g is found to contain 15.5% by mass nickel. What mass of nickel is contained in the ore? A) 10.5 g B) 81.7 g C) 1.55 g D) 84.5 g E) 546 g

Q: An ore sample is found to contain 24.1 g of mercury and 50.7 g waste rock (gangue). What is the percent by mass of mercury in the ore? A) 32.2 % B) 47.4 % C) 0.322 % D) 0.474 % E) 4.74 %

Q: In 1928, 1.0g of rhenium, Re, was isolated from 660kg of the ore molybenite. The percent by mass of this element in the molybenite wasA) 0.66 %.B) 0.15 %.C) 3.5 x10-4 %.D) 6.6 x10-3 %.E) 1.5 x10-4 %.

Q: Which of the following samples contains the largest number of molecules? A) 10. g Pb B) 10. g Cl2 C) 10. g Kr D) 10. g O2 E) 10. g S8

Q: Which of the following samples contains the largest number of atoms? A) 1 g N2 B) 1 g Li C) 1 g Cl2 D) 1 g P4 E) 1 g Mg

Q: Which of the following samples contains the smallest number of molecules? A) 8.00 g of TNT, C7H5N3O6 B) 8.00 g of benzene, C6H6 C) 8.00 g of glucose, C6H12O6 D) 8.00 g of naphthalene, C10H8 E) 8.00 g of formaldehyde, CH2O

Q: A sample of 336g of ozone, O3, contains the same number of atoms as A) 336 g of oxygen (O2). B) 28.2 g of hydrogen (H2). C) 266 g of fluorine (F2). D) 189 g of aluminum (Al). E) 411 g of nickel (Ni).

Q: The total number of oxygen atoms in 1.76g of CaCO3(MM=100.0g/mol) isA) 2.05 x1023.B) 4.24 x1022.C) 3.18 x1022.D) 1.75 x1023.E) 5.30 x1022.

Q: A sample of 496g of white phosphorus, P4, contains the same number of atoms as A) 192 g of ozone (O3). B) 56.0 g of nitrogen (N2). C) 92.0 g of sodium. D) 120 g of formaldehyde (CH2O). E) 128 g of oxygen (O2).

Q: Which one of the following contains 2.41x1024 atoms?A) 52.0 g C2H2B) 96.0 g O2C) 32.0 g CH4D) 168 g N2E) 16.0 g He

Q: How many aluminum atoms are there in 52g of Al2S3?A) 4.2 x1023B) 1.6 x1021C) 2.1 x1023D) 1.1 x1021E) 6.3 x1023

Q: Which is a reasonable mass corresponding to 1020 molecules of a substance? A) 100 g B) 100 g C) 100 ng D) 100 mg E) 100 kg

Q: In 0.500mol of dimethylhydrazine, (CH3)2N2H2, there areA) 3.01 x1024molecules.B) 1.51 x1023atoms.C) 3.01 x1022molecules.D) 3.61 x1024atoms.E) 1.81 x1024atoms.

Q: Styrene's empirical formula is CH. When it is heated to 200ºC, it is converted into a polymer, polystyrene, which has excellent insulating properties. What mass of styrene contains 9.75x1021molecules of styrene? The molar mass of styrene is 104g/mol.A) 0.0162 gB) 1.68 gC) 3.24 gD) 0.210 gE) 0.130 g

Q: How many atoms are present in 463g of KPF6(MM=184.1g/mol)?A) 2.23 x1025B) 1.51 x1021C) 2.51 x1021D) 1.13 x1026E) 1.21 x1025

Q: How many molecules are there in 2.43mg of mannose, C6H12O6, which is a sweet-tasting sugar that has a bitter aftertaste?A) 4.46 x1021B) 2.48 x1021C) 7.31 x1018D) 4.04 x1024E) 8.13 x1018

Q: How many molecules are there in 2.80kg of hydrazine, N2H4?A) 8.75 x1023B) 5.27 x1025C) 1.88 x1022D) 2.80 x1026E) 4.65 x1021

Q: In 0.358mol of trimellitic acid, C6H3(COOH)3, there areA) 2.16 x1022molecules.B) 8.62 x1024molecules.C) 6.47 x1023oxygen atoms.D) 1.94 x1024carbon atoms.E) 3.59 x1023hydrogen atoms.

Q: How many molecules are there in 192g of citric acid, C6H8O7?A) (6.02 x1023) / 192B) 192C) 6.02 x1023D) 96.0E) 192 x(6.02 x1023)

Q: How many molecules are there in 90.0g of butylene glycol, HO(CH2)4OH?A) 1B) (6.02 x1023)/90.0C) 90.0D) 90.0 x(6.02 x1023)E) 6.02 x1023

Q: A 0.0103-mol sample of urea, NH2CONH2, containsA) 6.02 x1023molecules.B) 2.48 x1022molecules.C) 4.96 x1022atoms.D) 2.48 x1023atoms.E) 1.03 x1024atoms.

Q: How many moles of silver are contained in 7.00kg of silver?A) 64.9 molB) 64.9 x101molC) 64.9 x10-3 molD) 64.9 x103molE) 64.9 x10-1mol

Q: Sodium cyclamate, C6H11NHSO3Na, was used at one time as an artificial sweetener. C6H11NHSO3Na has a molecular mass of 201.2g/mol. How many moles of sodium cyclamate are contained in a 67.6-g sample? A) 0.211 mol B) 0.193 mol C) 0.336 mol D) 0.307 mol E) 13,600 mol

Q: How many moles of pentane, C5H12, are contained in a 11-g sample? A) 0.18 mol B) 0.15 mol C) 0.26 mol D) 1.4 mol E) 1.1 mol

Q: How many moles of iron atoms are contained in 4.39g of iron? A) 245 mol B) 0.0579 mol C) 0.0786 mol D) 0.122 mol E) 0.169 mol

Q: How many moles of hexachlorobenzene, C6Cl6, are in 4.45g of C6Cl6?A) 0.0208 molB) 1.27 x103molC) 0.0618 molD) 0.0156 molE) 0.0322 mol

Q: Calculate the number of moles of bromine present in 14.5mL of Br2(l), whose density is 3.12g/mL. A) 3.53 mol B) 0.181 mol C) 0.566 mol D) 0.091 mol E) 0.283 mol

Q: Which of the following contains the greatest mass of oxygen atoms?A) 0.6 mol CoSO4+ 7H2OB) 2.3 mol KHSO4C) 1.2 mol K2Cr2O7D) 2.3 mol H2O2E) 2.3 mol Na2S2O3

Q: Which one of the following samples has the greatest mass? A) 0.39 mol of camphor, C10H16O B) 4.1 mol of ammonia, NH3 C) 9.2 mol of krypton, Kr D) 4.6 mol of iodine vapor, I2 E) 1.8 mol of formaldehyde, CH2O

Q: What is the mass in grams of 0.699mol of glucose, C6H12O6? A) 0.00388 g B) 67.1 g C) 126 g D) 21.0 g E) 258 g

Q: What is the mass of oxygen atoms in 0.305mol Fe(CO)5? A) 17.0 g B) 59.7 g C) 24.4 g D) 4.88 g E) 18.3 g

Q: Styrene's empirical formula is CH. What mass of styrene contains 7.89x1021atoms of hydrogen? The molar mass of styrene is 104g/mol.A) 0.105 gB) 0.170 gC) 1.36 gD) 0.157 gE) 0.0131 g

Q: Consider the following three samples. A) A sample containing 180g glucose (C6H12O6) B) A sample containing 90g glucose and 90g fructose (C6H12O6) C) A sample containing 180g fructose Which statement is correct? A) All three samples have the same number of hydrogen atoms. B) Both samples A and C have the same number of hydrogen atoms, but more than in sample B. C) Sample B has more hydrogen atoms than sample A or sample C. D) Sample C has more hydrogen atoms than sample A or sample B E) Sample A has more hydrogen atoms than sample B or sample C.

Q: Sorbose, C6H12O6, is used in making vitamin C. A sorbose sample containing 96.0 g of carbon atoms also contains ____ g of hydrogen atoms.A) 32.2B) 16.1C) 1.15 x103D) 96.0E) 7.99

Q: A sample of gallium(III) sulfite, Ga2(SO3)3, contains 1.95mol of sulfite ions. The number of moles of gallium(III) ions in the sample is A) 1.30 mol. B) 2.92 mol. C) 1.95 mol. D) 5.84 mol. E) 3.90 mol.

Q: A sample of ammonium phosphite, (NH4)3PO3, contains 0.909mol of hydrogen atoms. The number of moles of oxygen atoms in the sample is A) 0.227 mol. B) 0.0909 mol. C) 0.300 mol. D) 0.227 mol. E) 3.00 mol.

Q: How many atoms of carbon are there in 0.51mol of procaine, C13H20N2O2, a "pain killer" used by dentists?A) 6.6 x1023B) 4.3 x1024C) 4.0 x1024D) 6.1 x1023E) 4.6 x1024

Q: Which of the following compounds contains the largest number of atoms? A) 4.0 mol of K2S B) 3.0 mol of NH3 C) 2.0 mol of H2SO4 D) 5.0 mol of HCl E) 1.0 mol of CH3COCl

Q: What is the mass of oxygen in grams found in one molecule of the compound C7H8O4?A) gB) gC) gD) gE) 156 g

Q: What is the mass in grams of one propene, C3H6, molecule?A) 6.99 x10-23gB) 2.53 x1025gC) 44.0 gD) 42.0 gE) 1.99 x10-23 g

Q: An atom of an element weighs 3.00x10-23g. What is the atomic mass of this element in atomic mass units?A) 17.4 amuB) 16.5 amuC) 15.9 amuD) 18.1 amuE) 15.3 amu

Q: Monodisperse polyacrylonitrile contains molecules with the general formula -(CH2CHCN)n-, where nis typically greater than 10,000. Given that a sample of monodisperse polyacrylonitrile weighs 252.6 g and contains molecules of -(CH2CHCN)n-, what is the molar mass of the polymer? A) g/mol B) g/mol C) g/mol D) g/mol E) g/mol

Q: Monodisperse polyacrylonitrile contains molecules with the general formula -(CH2CHCN)n-, where nis typically greater than 10,000. Given that a sample of monodisperse polyacrilonitrile weighs 197.4 g and contains molecules of -(CH2CHCN)n-, calculate n. A) B) C) D) E)

Q: A 1.067g sample of an element contains 5.062x1021atoms. What is the element symbol?A) IB) AgC) LaD) PdE) Rh

Q: What is the molar mass of the solid C8H12N2O4? A) 172 g/mol B) 136 g/mol C) 200 g/mol D) 106 g/mol E) 188 g/mol

Q: The dicarboxylic acid potassium hydrogen pthalate (shown in the figure) is used to standardize solutions of strong base. What is the molar mass of this compound? A) 204.2 g/mol B) 192.2 g/mol C) 248.9 g/mol D) 71.08 g/mol E) 172.2 g/mol

Q: Plastic wrap can be made from poly(vinylidene chloride). A single poly(vinylidene chloride) strand has the general formula -(CH2CHCl)n-, where nranges from 10,000 to 100,000. What is the molar mass of a single poly(vinylidene chloride) molecule containing repeating units? A) g/mol B) g/mol C) g/mol D) g/mol E) g/mol

Q: What is the molar mass of zinc sulfate heptahydrate, ZnSO4+ 7H2O?A) 180. g/molB) 288 g/molC) 384 g/molD) 162 g/molE) 582 g/mol

Q: What is the molar mass of ammonium sulfite, (NH4)2SO3? A) 98 g/mol B) 116 g/mol C) 55 g/mol D) 180 g/mol E) 84 g/mol

Q: What is the molecular mass of the hydrocarbon styrene (shown in the figure)? A) 104.1 amu. B) 91.1 amu. C) 103.1 amu. D) 13.0 amu. E) 78.1 amu.

Q: What is the formula mass of strontium phosphate, Sr3(PO4)2? A) 357.83 amu B) 421.83 amu C) 182.59 amu D) 715.66 amu E) 452.80 amu

Q: What is the molecular mass of cycloheptane, C7H14? A) 13.02 amu B) 1191.19 amu C) 85.08 amu D) 98.19 amu E) 26.12 amu

Q: The fully hydrated form of sodium sulfate is the decahydrate, Na2SO4 + 10H2O. When heated the hydrated salt loses water. How many water molecules are found per formula unit in a partially dehydrated sample of sodium sulfate with a formula mass of 160.1 amu (i.e. find n for Na2SO4 + nH2O)?A) 1 waters.B) 5 waters.C) 3 waters.D) 4 waters.E) 7 waters.

Q: The formula mass of zinc acetate trihydrate, Zn(CH3COO)2 . 3H2O, isA) 321 amu.B) 184 amu.C) 268 amu.D) 238 amu.E) 114 amu.

Q: The formula mass of aluminum oxalate, Al2(C2O4)3, is A) 140 amu. B) 318 amu. C) 283 amu. D) 213 amu. E) 185 amu.

Q: A single molecule of polystryene has the repeating unit -[CH2CH(C6H5)]n-, where nis the number of repeating units. What is the value of nif the molecular mass of a single polymer chain is amu? A) units. B) units. C) units. D) units. E) units.

Q: The hydrocarbon heptane has the structural formula CH3(CH2)5CH3. What is the molecular mass of this hydrocarbon? A) 100.2 amu. B) 0.009980 amu. C) 86.17 amu. D) 0.01160 amu. E) 110.2 amu.

Q: The molecular formula of a particular solid is C8H6O8. Its molecular mass is A) 352 amu. B) 118 amu. C) 364 amu. D) 230 amu. E) 226 amu.

Q: Which of the following statements best describes the particulate representation depicted by the picture? A) The figure is a representation of a gas made up of a single element. B) The figure is a representation of a liquid mixture of two elements. C) The figure is a representation of a molecular solid. D) The figure is a representation of a liquid mixture of two compounds. E) The figure is a representation of a gas of a compound.

Q: Which of the following is/are postulates of Dalton's atomic theory? 1) Atoms combine in fixed ratios of whole numbers. 2) Atoms of each element have different properties. 3) Elements occur as solids, liquids, or gases. A) 1 only B) 2 only C) 3 only D) 1 and 2 E) 1, 2, and 3

Q: Which of the following equations is not balanced?A) 2Sb2OS2+ 10O2 → 2Sb2O5+ 4SO3B) (NH4)2Cr2O7→N2+ 4H2O + Cr2O3C) C12H22O11+ 12O2 → 12CO2+ 11H2OD) 2NaCl + Pb(NO3)2 → PbCl2+ 2NaNO3E) Fe3O4+ 3CO → 3Fe + 3CO2

Q: Which of the following chemical equations is not balanced?A) NH4NO3 → N2O + 2H2OB) C12H22O11 → 12C + 11H2OC) 2NH4SCN + Ba(OH)2 + 8H2O → 2NH3+ 10H2O + Ba(SCN)2D) (NH4)2Cr2O7 → N2O + Cr2O3+ 4H2OE) 2Mg + CO2 → 2MgO + C

Q: Which one of the following equations is properly balanced?A) Sn + 4HNO3→SnO2+ 4NO2+ 2H2OB) 2Na2SO4+ 3Bi(NO3)3 → Bi2(SO4)3+ 9NaNO3C) CH3CHO + 3O2→ 2CO2+ 2H2OD) NH4NO3 → 2H2O + N2E) Na2CO3+ 2H2SO4 → Na2SO4+ 2H2O + CO2

Q: Ammonia can be made by reaction of water with magnesium nitride:__ Mg3N2(s) + __ H2O(l) → __ Mg(OH)2(s) + __ NH3(g)When the equation is properly balanced, the sum of the coefficients isA) 6.B) 14.C) 12.D) 9.E) 8.