CHM 101 Exam 2 Practice Problems

Three students wrote chemical formulas to represent the diagram below. For each
response, indicate if they are correct or not and why.

• S3O incorrect formula says 3 S atoms bonded to 1 O atom

• S6O18 is incorrect formula says 6 S atoms bonded to 18 O atoms

• SO3 correct

How do you tell if a compound is considered ionic or covalent? What characteristics
do you use to make the distinction?

An ionic compound must be made up of ions. What ions make up each of the following:

a. Ca(OH)2 b. Al 2 (CO 3 )3

• 1 Ca2+ ion and 2OH- ions

• 2 Al3+ ions and 3CO3'2- ions

• Ca1+ ions

• AlCO3+ ions

What is the name of Ca(OH)2 ?

What is the name of S2O4 ?

What is the formula for tetrachlorine difluoride?

• Cl4F2
• Cl2F4
• ClF6
• Cl3F

What is the formula for cobalt (III) sulfate?

• Co2(SO4)3
• Co2(SO3)3
• Co(SO4)3
• Co3(SO4)2

What is the name of C4H10 ?

How can we use the periodic table to determine the number of valence electrons an
atom has & the ion charge it forms?

There are two types of ions: cations and anions. What is the difference between the
two? Relate this to protons & electrons.