Question 1

Calculate the molar mass of rubidium carbonate, Rb2CO3.

Accepted Answer

A)   340.43 g/mol
B)   255.00 g/mol
C)   230.94 g/mol
D)   145.47 g/mol
E)   113.48 g/molF) B) and E)
G) A) and B)

Question 2

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides)  are needed to form 485 g of sulfur tetrafluoride? 3SCl2(l)  + 4NaF(s)   →\rightarrow→  SF4(g)  + S2Cl2(l)  + 4NaCl(s)

Accepted Answer

A)   1940 g
B)   1510 g
C)   754 g
D)   205 g
E)   51.3 g F) A) and B)
G) A) and C)

Question 3

What volume, in L, of 10.0 M HCl is needed to make 2.00 L of 2.00 M HCl solution by dilution with water?

Accepted Answer

A)   0.800 L
B)   0.400 L
C)   0.200 L
D)   0.100 L
E)   None of these choices is correct.F) None of the above
G) B) and D)

Question 4

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Accepted Answer

A)   9.490 *1025 Cr atoms
B)   2.248 * 1024 Cr atoms
C)   1.124 * 1024 Cr atoms
D)   3.227 *1023 Cr atoms
E)   1.613 * 1023 Cr atomsF) C) and D)
G) A) and E)

Question 5

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO2 and H2O, respectively, which are collected in the absorbers.

Accepted Answer

A) True 
 B)False

Question 6

A compound consisting of C, H and O only, has a molar mass of 331.5 g/mol. Combustion of 0.1000 g of this compound caused a 0.2921 g increase in the mass of the CO2 absorber and a 0.0951 g increase in the mass of the H2O absorber. What is the empirical formula of the compound?

Accepted Answer

Question 7

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Accepted Answer

A)   43.3 g
B)   62.3 g
C)   74.5 g
D)   92.9 g
E)   107 gF) A) and B)
G) A) and E)

Question 8

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. If its molar mass is between 158 and 167 g/mol, what is its molecular formula?

Accepted Answer

A)   C4H6O7
B)   C6H8O5
C)   C7H12O4
D)   C4H3O2
E)   C8H6O4F) None of the above
G) B) and D)

Question 9

Alkanes are compounds of carbon and hydrogen with the general formula CnH2n+2. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

Accepted Answer

A)   4
B)   9
C)   10
D)   13
E)   14F) All of the above
G) A) and C)

Question 10

Aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent, desiccant or catalyst for organic reactions. 
4Al(s)  + 3O2(g)   →\rightarrow→ 2Al2O3(s) 
A mixture of 82.49 g of aluminum (? = 26.98 g/mol)  and 117.65 g of oxygen (? = 32.00 g/mol)  is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

Accepted Answer

A)   Oxygen is the limiting reactant; 19.81 g of aluminum remain.
B)   Oxygen is the limiting reactant; 35.16 g of aluminum remain.
C)   Aluminum is the limiting reactant; 16.70 g of oxygen remain.
D)   Aluminum is the limiting reactant; 35.16 g of oxygen remain.
E)   Aluminum is the limiting reactant; 44.24 g of oxygen remain. F) A) and B)
G) All of the above

Question 11

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. 
1. IO3¯(aq)  + 5I¯(aq)  + 6H+(aq)   →\rightarrow→ 3I2(aq)  + 3H2O(l) 
2. I2(aq)  + 2S2O32¯(aq)   →\rightarrow→  2I¯(aq)  + S4O62¯(aq) 
The molecular iodine (I2)  formed in reaction 1 is immediately used up in reaction 2, so that no iodine accumulates. In one experiment, a student made up a reaction mixture which initially contained 0.0020 mol of iodate ions (IO3¯) . If the iodate ions reacted completely, how many moles of thiosulfate ions (S2O32¯)  were needed in reaction 2, in order to react completely with the iodine (I2)  produced in reaction 1?

Accepted Answer

A)   0.0020 mol
B)   0.0030 mol
C)   0.0040 mol
D)   0.0050 mol
E)   0.0060 mol F) C) and D)
G) A) and C)

Question 12

How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO3 (? = 84.02 g/mol) ? 
HCl(aq)  + NaHCO3(s)   →\rightarrow→  NaCl(s)  + H2O(l)  + CO2(g)

Accepted Answer

A)   638 mL
B)   572 mL
C)   536 mL
D)   276 mL
E)   175 mL F) None of the above
G) A) and C)

Question 13

Calculate the molar mass of (NH4) 3AsO4.

Accepted Answer

A)   417.80 g/mol
B)   193.03 g/mol
C)   165.02 g/mol
D)   156.96 g/mol
E)   108.96 g/molF) A) and B)
G) A) and C)

Question 14

Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be used as a drying agent.

Accepted Answer

A)   469.73 g/mol
B)   283.89 g/mol
C)   190.97 g/mol
D)   139.88 g/mol
E)   94.97 g/molF) B) and E)
G) B) and D)

Question 15

A single atom of hydrogen has a mass of 1.0 amu, while a mole of hydrogen atoms has a mass of 1.0 g. Select the correct conversion factor between atomic mass units and grams.

Accepted Answer

A)   1 amu = 1 g exactly
B)   1 amu = 6.0 *1023 g
C)   1 g = 6.0 * 1023 amu
D)   1 g = 1.7 *10¯24 amu
E)   None of these choices is correct.F) B) and D)
G) A) and C)

Question 16

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Accepted Answer

A) True 
 B)False

Exam 3: Stoichiometry of Formulas and Equations

A compound consisting of C, H and O only, has a molar mass of 331.5 g/mol. Combustion of 0.1000 g of this compound caused a 0.2921 g increase in the mass of the CO₂ absorber and a 0.0951 g increase in the mass of the H₂O absorber. What is the empirical formula of the compound?

Correct Answer
verified

Calculate the molar mass of (NH₄) ₃AsO₄.

Correct Answer
verified

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Correct Answer
verified

Alkanes are compounds of carbon and hydrogen with the general formula C_nH₂_n₊₂. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

Correct Answer
verified

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

Correct Answer
verified

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) $\rightarrow$ SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

Correct Answer
verified

Correct Answer
verified

How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO₃ (? = 84.02 g/mol) ? HCl(aq) + NaHCO₃(s) $\rightarrow$ NaCl(s) + H₂O(l) + CO₂(g)

Correct Answer
verified

A single atom of hydrogen has a mass of 1.0 amu, while a mole of hydrogen atoms has a mass of 1.0 g. Select the correct conversion factor between atomic mass units and grams.

Correct Answer
verified

Correct Answer
verified

What volume, in L, of 10.0 M HCl is needed to make 2.00 L of 2.00 M HCl solution by dilution with water?

Correct Answer
verified

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO₂ and H₂O, respectively, which are collected in the absorbers.

Correct Answer
verified

Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
verified

Correct Answer
verified

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Correct Answer
verified

Calculate the molar mass of tetraphosphorus decaoxide, P₄O₁₀, a corrosive substance which can be used as a drying agent.

Correct Answer
verified

Exam 3: Stoichiometry of Formulas and Equations

A compound consisting of C, H and O only, has a molar mass of 331.5 g/mol. Combustion of 0.1000 g of this compound caused a 0.2921 g increase in the mass of the CO2 absorber and a 0.0951 g increase in the mass of the H2O absorber. What is the empirical formula of the compound?

Correct AnswerverifiedShow Answer

Calculate the molar mass of (NH4) 3AsO4.

Correct AnswerverifiedShow Answer

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Correct AnswerverifiedShow Answer

Alkanes are compounds of carbon and hydrogen with the general formula CnH2n+2. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

Correct AnswerverifiedShow Answer

Calculate the molar mass of rubidium carbonate, Rb2CO3.

Correct AnswerverifiedShow Answer

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl2(l) + 4NaF(s) →\rightarrow→ SF4(g) + S2Cl2(l) + 4NaCl(s)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO3 (? = 84.02 g/mol) ? HCl(aq) + NaHCO3(s) →\rightarrow→ NaCl(s) + H2O(l) + CO2(g)

Correct AnswerverifiedShow Answer

A single atom of hydrogen has a mass of 1.0 amu, while a mole of hydrogen atoms has a mass of 1.0 g. Select the correct conversion factor between atomic mass units and grams.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What volume, in L, of 10.0 M HCl is needed to make 2.00 L of 2.00 M HCl solution by dilution with water?

Correct AnswerverifiedShow Answer

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO2 and H2O, respectively, which are collected in the absorbers.

Correct AnswerverifiedShow Answer

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Correct AnswerverifiedShow Answer

Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be used as a drying agent.

Correct AnswerverifiedShow Answer

A compound consisting of C, H and O only, has a molar mass of 331.5 g/mol. Combustion of 0.1000 g of this compound caused a 0.2921 g increase in the mass of the CO₂ absorber and a 0.0951 g increase in the mass of the H₂O absorber. What is the empirical formula of the compound?

Correct Answer
verified

Calculate the molar mass of (NH₄) ₃AsO₄.

Correct Answer
verified

Correct Answer
verified

Alkanes are compounds of carbon and hydrogen with the general formula C_nH₂_n₊₂. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

Correct Answer
verified

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

Correct Answer
verified

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) $\rightarrow$ SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

Correct Answer
verified

Correct Answer
verified

How many milliliters of 1.58 M HCl are needed to react completely with 23.2 g of NaHCO₃ (? = 84.02 g/mol) ? HCl(aq) + NaHCO₃(s) $\rightarrow$ NaCl(s) + H₂O(l) + CO₂(g)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In combustion analysis, the carbon and hydrogen contents of a substance are determined from the CO₂ and H₂O, respectively, which are collected in the absorbers.

Correct Answer
verified

Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Calculate the molar mass of tetraphosphorus decaoxide, P₄O₁₀, a corrosive substance which can be used as a drying agent.

Correct Answer
verified