Chem 121 Exam 2 Final Paper Verified Questions Accurate Solutions

CHEM 121 EXAM 2 FINAL PAPER VERIFIED QUESTIONS ACCURATE SOLUTIONS
CHEM 121 EXAM 2 Questions and Answers Verified
Solutions Latest Update 2026/2027

Question:
The molar mass of an element.

Answer:
is unique



Question:
The molar mass of a compound.

Answer:
lacks uniqueness



Question:
Molar mass is a.

Answer:
physical rather than chemical property of a substance



Question:
6.02 x 10^23 amu =.

Answer:
1.00 g



Question:
Which set of quantities is needed to calculate the molar mass of a compound?

Answer:

,chemical formula and atomic masses



Question:
The atomic mass of O is 16.00 amu. The molar mass for O atoms is.

Answer:
16.00 g



Question:
The atomic masses of N and O are, respectively, 14.01 amu and 16.00 amu. The molar mass of the
compound NO2 is.

Answer:
46.01 g



Question:
The molar mass of CO2 is 44.01 g. What is the mass, in amu, of one molecule of CO2?

Answer:
44.01 amu



Question:
The formula mass of N2O is 44.02 amu. What is the mass, in grams, of one-half mole of N2O?

Answer:
22.01 g



Question:
the subscripts in a formula always.

Answer:
carry dual meaning [atoms at microscopic level & moles of atoms at macroscopic level]

,Question:
Lactic acid, the substance that builds up in muscles and causes them to hurt when they are worked
hard, has the formula C3H6O3. How many moles of carbon atoms, hydrogen atoms, and oxygen
atoms are present in a 1.2-mole sample of lactic acid?

Answer:
3.6 mol C atoms, 7.2 mol H atoms, 3.6 mol O atoms



Question:
How many moles of H atoms are present in one mole of H3pO4 molecules?

Answer:
3 moles



Question:
Which of the following samples contains 4.0 moles of O atoms? a. 1.0 mole SO2 b. 2.0 moles SO2
c. 1.0 mole SO3 d. no correct response.

Answer:
2.0 moles SO2



Question:
The total number of moles of atoms present in 4.00 moles of CO2 is.

Answer:
12.0 moles



Question:
What is the needed conversion factor to convert from moles of N2H4 to moles of N?

Answer:
2 moles N/1 mole N2H4

, Question:
Vitamin C has the formula C6H8O6. Calculate the number of vitamin C molecules pre- sent in a
0.250-g tablet of pure vitamin C.

Answer:
8.54 x 10^20 molecules C6H8O6



Question:
How many grams of nitrogen are present in a 0.10-g sample of caffeine, the stimulant in coffee and
tea? The formula of caffeine is C8H10N4O2.

Answer:
0.029gN



Question:
The problem "How many molecules of H2O are present in 25.4 g of H2O?" is characterized as a.

Answer:
"grams of A" to "particles of A" problem



Question:
The pathway for solving a "grams of A" to "grams of B" problem using conversion factors is.

Answer:
grams A to moles A to moles B to grams B



Question:
How many conversion factors are needed in solving a "particles of A" to "grams of A" problem?

Answer:
2