Chemical Formula Practice Quiz
Questions: 16 · 10 minutes
1. A compound has the simplest whole-number mole ratio C:H:O = 1:2:1. What is its empirical formula?
CH2O
CO2
CHO
C2H4O2
2. In neutral Al2O3, each oxide ion has a charge of 2-. What charge must each aluminum ion have?
A charge of 1+
A charge of 2+
A charge of 3+
A charge of 6+
3. What does the 5H2O in CuSO4·5H2O indicate?
Five sulfate ions are dissolved in one water molecule.
Five hydrogen atoms are bonded directly to each sulfate ion.
Water makes up exactly five percent of the compound by mass.
Five water molecules are associated with each formula unit of CuSO4.
4. Ammonium is NH4+ and sulfate is SO4 2-. Which formula represents neutral ammonium sulfate?
NH4SO4, containing one ammonium ion per sulfate ion
(NH4)2(SO4)2, containing two of each ion
NH4(SO4)2, containing one ammonium ion and two sulfate ions
(NH4)2SO4, containing two ammonium ions per sulfate ion
5. How many oxygen atoms are represented in one molecule of H2SO4?
Seven oxygen atoms
One oxygen atom
Two oxygen atoms
Four oxygen atoms
6. Sodium forms Na+ ions and chlorine forms Cl- ions. Which neutral formula do they produce?
Na2Cl, using two sodium ions per chloride ion
NaCl, using a one-to-one ion ratio
NaCl2, using two chloride ions per sodium ion
Na2Cl2, an unreduced two-to-two ratio
7. A magnesium ion is Mg2+ and a chloride ion is Cl-. Which formula gives a neutral compound?
MgCl, with one chloride ion per magnesium ion
MgCl2, with two chloride ions per magnesium ion
Mg2Cl2, with an unreduced two-to-two ratio
Mg2Cl, with two magnesium ions per chloride ion
8. What is the empirical formula of C2H6?
CH3, the simplest one-to-three ratio
CH2, a one-to-two ratio
C2H6, the unreduced molecular formula
C2H3, a two-to-three ratio
9. Potassium forms K+ ions and phosphate is PO4 3-. What is the simplest neutral formula for potassium phosphate?
K3PO4, with three potassium ions per phosphate ion
K2PO4, with two potassium ions per phosphate ion
K3(PO4)3, with three potassium ions and three phosphate ions
KPO4, with one potassium ion per phosphate ion
10. Iron(III) ions are Fe3+ and oxide ions are O2-. Which formula represents neutral iron(III) oxide?
FeO, a one-to-one iron-to-oxygen ratio
Fe3O2, a three-to-two iron-to-oxygen ratio
Fe2O3, a two-to-three iron-to-oxygen ratio
FeO3, one iron ion combined with three oxide ions
11. Calcium forms Ca2+ ions, while nitrate is NO3-. What is the simplest formula for calcium nitrate?
CaNO3, with one nitrate group
Ca(NO3)2, with two nitrate groups
Ca2NO3, with two calcium ions per nitrate
Ca2(NO3)2, with an unbalanced two-to-two ratio
12. Aluminum ions are Al3+ and sulfate ions are SO4 2-. Which formula has balanced total charge?
AlSO4, with one aluminum ion and one sulfate ion
Al3(SO4)2, with three aluminum ions and two sulfate ions
Al2(SO4)3, with two aluminum ions and three sulfate ions
Al(SO4)3, with one aluminum ion and three sulfate ions
13. Which formula matches the covalent compound name dinitrogen pentoxide?
N2O5, with two nitrogen atoms and five oxygen atoms
NO5, with one nitrogen atom and five oxygen atoms
N5O2, with the prefix quantities reversed
N2O4, with four rather than five oxygen atoms
14. How many hydrogen atoms are represented by the expression 3H2O?
Nine hydrogen atoms
Two hydrogen atoms
Three hydrogen atoms
Six hydrogen atoms
15. How many oxygen atoms occur in one formula unit of Ca(OH)2?
One oxygen atom
Two oxygen atoms
Three oxygen atoms
Four oxygen atoms
16. A reagent label names the substance as phosphoric acid. Which formula belongs on the label?
H3PO3, the formula for phosphorous acid
HPO3, a one-hydrogen metaphosphate composition
H3PO4, the formula for phosphoric acid
H2PO4-, the dihydrogen phosphate ion