CHEM 121 FINAL EXAM Questions and
Answers | 2026 Step-by-Step Exam
Review | A+ Verified
• accuracy refers to -✓✓how close a measured number is to the true value
• the nucleus of an atom contains -✓✓protons and neutrons
• the nucleus of an atom DOES NOT contain -✓✓electrons
• isotopes are atoms that have the same ---- but differing ---- -✓✓atomic numbers ;
mass numbers
• the formula of nitrobenzene is C6H5NO2. The molecular weight of this compound is ---
- amu -✓✓123.11
• which one of the following molecular formulas is also an empirical formula? -
✓✓C2H6SO
• a small amount of salt dissolved in water is an example of a ---- -✓✓homogeneous
mixture
• the density of a gold nugget is 19.3 g/cm^3. if the volume of the gold nugget is
0.00369 L, the mass of the nugget is ---- -✓✓71.2
• the element X has three naturally occurring isotopes. the masses (amu) and %
abundances of the isotopes are given in the table below. the average atomic mass of
the element is ---- amu -✓✓220.4
• which species has 54 electrons -✓✓^128 52 Te ^2-
• these are all intensive properties -✓✓density, melting point, boiling point, temperature
• the symbol for the element potassium is -✓✓K
• of the reactions below, which one is a decomposition reaction -✓✓NH^4Cl --> NH^3 +
HCl
• solid aluminum and gaseous oxygen react in a combination reaction to produce
aluminum oxide
4Al(s) + 3O2(g) --> 2Al203
, The maximum amount of Al2O3 that can be produced from 2.5 g of Al and 2.5 g of O2
is ---- g -✓✓4.7
• the si unit of temperature is ---- -✓✓K
• what is the physical state in which matter has no specific shape but does have a
specific volume? -✓✓liquid
• the correct answer (reported to the proper number of sig figs) to the following is
1.268 x 0.23= -✓✓0.29
• There are ---- electrons, ---- protons, and ---- neutrons in an atom of ^132 54 Xe -
✓✓54;54;78
• which formula/name pair is incorrect -✓✓Fe2(SO4)3 iron (III) sulfide
• how many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide -✓✓1.08 x
10^24
• the number with the most significant zeros is -✓✓2.51000000
• lithium and nitrogen react to produce lithium nitride
6Li(s) + N2(g) --> 2Li3N(s)
How many moles of N2 are needed to react with 0.550 mol of lithium -✓✓0.0917
• which one of the following compounds is copper (I) bromide -✓✓CuBr
• when the following equation is balanced, the coefficients are ----
Al(NO3)3 + Na2S --> Al2S3 + NaNO3 -✓✓2;3;1;6
• The mass % of C in methane (CH4) is ---- -✓✓
• these are all strong bases -✓✓LiOH; NaOH; KOH; Ca(OH)2; Sr(OH)2; Ba(OH)2
• these are all strong acids -✓✓HClO4; HCl; HBr; HI; HNO3; H2SO4
• which one of the following is insoluble in water?
Na2S ; Ca(OH)2 ; AgCl ; Fe(NO3)2 ; (NH4)2SO4 -✓✓AgCl
• what is the precipitate that forms when KI(aq) reacts with Pb(NO3)2 (aq) -✓✓PbI2
• when aqueous solutions of AgNO3 and NaI are mixed, Agl precipitates. the balanced
net ionic equation is ---- -✓✓Ag ^+ (aq) + I ^- --> AgI (s)
Answers | 2026 Step-by-Step Exam
Review | A+ Verified
• accuracy refers to -✓✓how close a measured number is to the true value
• the nucleus of an atom contains -✓✓protons and neutrons
• the nucleus of an atom DOES NOT contain -✓✓electrons
• isotopes are atoms that have the same ---- but differing ---- -✓✓atomic numbers ;
mass numbers
• the formula of nitrobenzene is C6H5NO2. The molecular weight of this compound is ---
- amu -✓✓123.11
• which one of the following molecular formulas is also an empirical formula? -
✓✓C2H6SO
• a small amount of salt dissolved in water is an example of a ---- -✓✓homogeneous
mixture
• the density of a gold nugget is 19.3 g/cm^3. if the volume of the gold nugget is
0.00369 L, the mass of the nugget is ---- -✓✓71.2
• the element X has three naturally occurring isotopes. the masses (amu) and %
abundances of the isotopes are given in the table below. the average atomic mass of
the element is ---- amu -✓✓220.4
• which species has 54 electrons -✓✓^128 52 Te ^2-
• these are all intensive properties -✓✓density, melting point, boiling point, temperature
• the symbol for the element potassium is -✓✓K
• of the reactions below, which one is a decomposition reaction -✓✓NH^4Cl --> NH^3 +
HCl
• solid aluminum and gaseous oxygen react in a combination reaction to produce
aluminum oxide
4Al(s) + 3O2(g) --> 2Al203
, The maximum amount of Al2O3 that can be produced from 2.5 g of Al and 2.5 g of O2
is ---- g -✓✓4.7
• the si unit of temperature is ---- -✓✓K
• what is the physical state in which matter has no specific shape but does have a
specific volume? -✓✓liquid
• the correct answer (reported to the proper number of sig figs) to the following is
1.268 x 0.23= -✓✓0.29
• There are ---- electrons, ---- protons, and ---- neutrons in an atom of ^132 54 Xe -
✓✓54;54;78
• which formula/name pair is incorrect -✓✓Fe2(SO4)3 iron (III) sulfide
• how many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide -✓✓1.08 x
10^24
• the number with the most significant zeros is -✓✓2.51000000
• lithium and nitrogen react to produce lithium nitride
6Li(s) + N2(g) --> 2Li3N(s)
How many moles of N2 are needed to react with 0.550 mol of lithium -✓✓0.0917
• which one of the following compounds is copper (I) bromide -✓✓CuBr
• when the following equation is balanced, the coefficients are ----
Al(NO3)3 + Na2S --> Al2S3 + NaNO3 -✓✓2;3;1;6
• The mass % of C in methane (CH4) is ---- -✓✓
• these are all strong bases -✓✓LiOH; NaOH; KOH; Ca(OH)2; Sr(OH)2; Ba(OH)2
• these are all strong acids -✓✓HClO4; HCl; HBr; HI; HNO3; H2SO4
• which one of the following is insoluble in water?
Na2S ; Ca(OH)2 ; AgCl ; Fe(NO3)2 ; (NH4)2SO4 -✓✓AgCl
• what is the precipitate that forms when KI(aq) reacts with Pb(NO3)2 (aq) -✓✓PbI2
• when aqueous solutions of AgNO3 and NaI are mixed, Agl precipitates. the balanced
net ionic equation is ---- -✓✓Ag ^+ (aq) + I ^- --> AgI (s)
