Name: ___________________________Unit 5: Ionic Bonding Basics & Formulas

I.What is a bonding?_________________________________________________

__________________________________________________________________Types of Bonding:Electrons shared: ____________________________________________________Electrons transferred: ________________________________________________II. IONS:“+ion” __________________________________________ called _______________called: _____________ # electrons lost = _____________“-ion” __________________________________________ called _______________called: _____________ # electrons gained = ___________

III. Why do atoms form bonds? Let’s look at electron configuration again.Complete the chart below.For IONS: When a positive (+) ion forms, cross out the valence electrons of the atom’s configuration to get the new ion electron configuration. When a negative (-) ion forms, add electrons equal in to the negative charge to valence shell of the atom’s configuration to get the new ion electron configuration.

Atom Electron Configuration

# of Valence

electronsIt’s Ion Ion Electron

Configuration

# of e-1 nowin

outermost PEL

Na 2-8-1 1 Na+1 2-8-1 8

S 2-8-6 6 S-2 2-8-6 8 8

Mg

Ca

F

ClWhat seems to be the magic number, which shows up in the last column of the chart above? ________________ In which vertical group on the periodic table do all but one member have this magical number of valence electrons? _______________________ These elements are very stable and non-reactive. They are called the Noble Gases. They do not form compounds easily. Having this number of valance

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electrons is very stable. Atoms form bonds so that they can have this number of valence electrons and mimic the electron configuration of the noble gases. This is called the _____________________

What Noble Gas does each of elements mimic when it forms an ion? ex: Na has 11 electrons (EC: 2-8-1), Na+1 has 11 – 1 = 10 electrons so when Na

forms Na+1, its electron configuration (EC: 2-8) looks like Ne (atomic # 10)

S has 16 electrons (EC: 2-8-6), S-2 has 16 +2 = 18 electrons so when S forms S-2, its electron configuration (EC: 2-8-8) looks like Ar (atomic # 18

Atom Atom’s # ofelectrons

EC of Atom Ion Ion’s # of electrons

EC of ion Ion’s EC looks like

Mg Mg+2

Ca Ca+2

F F-1

Cl Cl-1

When metals form ions, the electron configuration looks like the __________________noble gas.When nonmetals form ions, the electron configuration looks like the noble gas at ______of its row.(We have not touched the nucleus, so the ions are still the same element that they were, but with different properties than their neutral atom!!)

IV. Dot Diagrams of Ions:Metals lose their valance electrons so a metal ion’s “Dot Diagram” is simply the ion’s symbol & Its charge ONLY- no dots: _____________Nonmetals gain enough valence electrons to make 8 valence electrons, so a nonmetal ion’s dot diagram is the symbol with 8 DOTS and its charge: ________

ION Dot diagram

ION Dot diagram

ION Dot diagram

ION Dot diagram

Ca+2 F-1 Al+3 O-2

Li+1 S-2 N-3 Mg+2

V. IONIC BONDING BASICSWhen metals and nonmetals react together, the metal gives always its valence electrons to the nonmetal forming positive ions whose positive charge is equal to the number of valence electrons lost. The nonmetal becomes a negative ion whose negative charge is equal to the number of valence

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electrons it has gained. The positive ion, called the cation, and the negative ion, called the anion, are then attracted to each other forming a new compound. The three steps in forming an ionic bond are:

1) _________________________________________________________2) _________________________________________________________3) _________________________________________________________

Neutral Metal’s Dot Diagram

Neutral Nonmetal’s Dot Diagram

Transfer of electrons from Metal to Nonmetal

ResultingDot Diagram

Formula

Na F

Ca Br

Mg O

K S

Al Cl

The number of each type of ion that will form the new compound will depend on the size or magnitude of the charges. The charges must add up to zero. For example, if sodium reacts with chlorine, sodium forms a Na+1 ion and chlorine forms a Cl-1 ion. Only one of each ion is necessary because the charges add up to zero: (+1) + (-1) =0 and the formula of the new compound, sodium chloride, is

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simply NaCl. If sodium reacts with oxygen, it still forms an ion with a +1 charge but oxygen will form an anion with a -2 charge. The new compound, sodium oxide, will require 2 Na+1 for every O-2: 2(+1) + (-2) =0 . The formula for sodium oxide is Na2O. Remember the charges are written as superscripts (Na+1) and the counters in formulas are written as subscripts (Na2O). Positive ions are written first and negative ions are written second in a formula. Lazy chemists do not bother to write 1 as counter in a formula. The element's symbol stands for the 1. Ionic formulas are always written in lowest terms. This is known as an empirical formula. These are binary (2 element) ionic compounds. VI. DETERMINING CHARGES: To determine the charge that an atom has on the periodic table, simply look at the upper right corner for the oxidation states of the element. The oxidation state or number is the charge or apparent charge an atom has in a compound. For nonmetals it is the FIRST (top) oxidation state ONLY. For many metals, there is only one possibility for the charge. Transition metals and those metals close to the “crack”, there are more than one charge. Look up the charges on the following: Remember to write the charges as superscripts!

Sr Ag Cl N Cs

O Fe Fe Cu Cu P Br

WRITING BINARY FORMULASThe ions of the elements combine in such a way that the charges have to add up to zero. The metal or positive ion (cation) is written FIRST and the nonmetal or negative ion (anion) is written SECOND. The number one, 1, is generally not written in the formula: ex. NaCl. Only the number in the charge for each ion is criss-crossed down and turned into subscripts. Always check that the formula is in LOWEST terms.

K+1 O-2 K O K2O1 or K2O Pb+4 O-2 -> Pb O -> Pb2O4 simplifies to ________Ions to be Bonded

How to determine formula Cation Anion Formula

X+1 and Y-1 +1 and -1 add up to zero alreadyX+2 and Y-2 +2 and -2 add up to zero alreadyX+3 and Y-3 +3 and -3 add up to zero alreadyX+2 and Y-1 It takes two -1 charges to cancel out

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the +2 chargeX+3 and Y-1 It takes three -1 charges to cancel out

the +3 chargeX+1 and Y-2 It takes two +1 charges to cancel out

the -2 chargeX+1 and Y-3 It takes three +1 charges to cancel out

the -3 chargeX+2 and Y-3 Common denominator: 2x3=6 it takes

three +2 to make +6 and two -3 to make -6

X+3 and Y-2 Common denominator: 2x3=6 it takes two +3 to make +6 and three -2 to make -6

X+4 and Y-2 It takes two -2 charges to cancel out the +4 charge

VII. NAMINGTo name ionic compounds, the name of the positive ion is followed by the name of the negative ion. Group 1 & 2 Metals, Metals with ONE charge LISTED: name of the metal ONLY

Metal Ion Ion’s Name Metal Ion

Ion’s Name

Na+1 Zn+2

Ca+2 Cd+2 Ag+1 Al+3

Transition Metals and Those under the “crack” with MORE THAN 1 CHARGE listed: name of metal + the Roman numeral EQUAL to the charge on the ionMetal Ion Ion’s Name Metal

IonIon’s Name

Au+1 Au+3

Pb+2 Pb+4 Fe+2 Fe+3

For nonmetals, the ending of the nonmetal’s name with the ending changed to IDE. Nonmetal Ion

Ion’s Name Nonmetal Ion

Ion’s Name

F-1 N-3

Cl-1 O-2 Br-1 P-3

I-1 S-2

To name ionic compounds, the name of the positive ion is followed by the name of the negative ion.Examples:

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NaF: sodium fluoride AlN: aluminum nitride AgBr: silver bromideNa3P: sodium phosphide Li2O lithium oxide PbCl2 lead (II) chloride

Try your hand at these! Write the formula and name of these compounds

Cation

Anion Formula Name

ex.

Mg+2 Br-1 MgBr2 Magnesium Bromide

1.) Li+1 F-1

2.) Al+3 Cl-1

3.) Sr+2 S-2

4.) K+1 N-3

5.) Mg+2 P-3

Go Backwards: Given the name, determine the elements involved and their charges & then write the formulas. Look up charges on the PT for the ions.

Name Cation Anion Formula1.)

Sodium Bromide

2.)

Calcium Oxide

3.)

Zinc Chloride

4.)

Beryllium Fluoride

5.)

Potassium Iodide

VIII. DETERMINING CHARGES AND NAMING of TRANSITION ELEMENTSTransition elements (metals), which are located in the short groups in the center of the periodic table and some other metals located near the “crack”, can have more than one charge. Either you will be told which one to use or the charge can be determined from the formula, which contains the element. To distinguish between the different oxidation states or charges of these transition metals, a roman numeral equal to the charge on the ion is used to name the ion. For example, tin comes in two charges, +2 and +4. Sn+2 is called tin (II) and Sn+4 is called tin (IV). The formula of tin (II) oxide is SnO and the formula of tin (IV) oxide is SnO2. The charge on the tin makes a difference!

AuCl: gold (I) chloride AuCl3: gold (III) chloride

If Fe2O3 is iron (III) oxide, what would be the formula for iron (II) oxide? _____

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ROMAN NUMERALS: +1 ____, +2 ____, +3 _____, +4 ____, +5 _____, +6 ______

Write the formula and name of these compounds with transition metals:Cation Anion Formula Name

ex.

Pb+2 Cl-1 PbCl2 lead (II) chloride

1. Cu+1 O-2

2. Ni+3 S-2

3. Fe+2 I-1

4. Au+1 N-3

5. Pb+4 O-2

Going Backwards! First, look up the charges of the elements given on the periodic table, then write the formula. Remember transition metals with roman numerals tell you what charge to use for the metal (first element): gold (III) chloride tells you to use Au+3 and NOT Au+1

Name Cation Anion Formula ex.

Iron (II) iodide Fe+2 I-1 BaI2

1. Copper (I) fluoride2. Copper (II) chloride3. Gold (III) oxide4. Tin (IV) oxide5. Lead (II) phosphideNaming the Ionic Compounds from JUST the FormulaDetermine if it has a metal with more than 1 charge or not (look up the metal on the P.T.) (transition or under the crack with more than one charge)- If yes, then look up the nonmetal’s charge and write the formula with

each of the charges. - Ex . FeO Fe+2 O-2 FeO

Fe+3 O-2 Fe2O3- Whichever formula matches, was the charge on the transition metal that

was used. Since the formula with Fe+2 matches, FeO, then Fe+2

was used.- Use the Roman numeral equal to this charge in the middle of the

compound’s name. Iron (II) - Change the name of the non-metal to the ending “ide”. Oxide- Iron (II) Oxide

- If no, then just use the metal’s name and change the name of the non-metal to the ending “ide”.

Ex. AgCl Ag+1 +1 is the only charge so its Silver ChlorideRemember any element in Groups 1 & 2 have ONLY one Charge!! No Roman Numeral ever!!!

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Formula

Possible Cation(s)

Anion Possible formula(s)

Name

Ni2O3 Ni+2, Ni+3 O-2 NiO, Ni2O3 Nickel (III) oxideLiF

PbO2

SnO

Na3P

ZnBr2

Fe2O3

AuI3

CrN

CuO

Ca3N2

IX. POLYATOMIC IONS (PAI)A. Reference Table ESometimes groups of atoms bond together by sharing electrons to form ions. This is known as covalent bonding. Here, one of the atoms in the group brings along a charge and group of atoms is not neutral. These ions are called polyatomic ions, which means “many atom” ion. Reference table E contains the formula and name of some of these polyatomic ions. Complete this chart using reference table E.

What type of charge do most of the PAI have? __________________Most of these PAI end in _________ or _____________

PAI name Formula PAI Formula

Name

ex.

Ammonium NH4+1 ex.

MnO4 - Permanganate

1. Nitrate 6. CO3 -2

2. Chlorite 7. C2H3O2 -

3. Chromate 8. SO4 -2

4. Sulfite 9. ClO3 -

5. Phosphate 10.

OH-

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Two important exceptions are the positive ion _________ (ammonium) and the negative ion _________ (hydroxide).B. Writing and Naming Compounds with Polyatomic IonsWhen forming compounds with these polyatomic ions, the same rules are followed for other ionic compounds. The formula must be in lowest terms and the charges must add up to zero. Parenthesis are used around the polyatomic ion when more than one of these ions is necessary in a formula: (NH4)2O. We want two NH4+ groups and NOT 42 H’s!!!To name compounds with polyatomic ions, follow the rules above but for the polyatomic ions, use the name of the polyatomic ion listed on the reference table.

Ex: (NH4)2O is ammonium oxide; K2CO3 is potassium carbonate. Compounds with at least one polyatomic ion are called ternary ionic compounds- more than 2 elements. You can recognize that these compounds have a polyatomic ion because there is more than two capital letters in the formula!!

ternary ionic compounds: K2CO3 and NaClO4binary ionic compounds: K2O and NaCl

Try your hand at these! Write the formula and name of these compounds: don’t forget the parenthesis!!

Cation Anion Formula Nameex.

Mg+2 ClO-1 Mg(ClO)2 Magnesium hypochlorite

1. K+1 NO3 -1

2. Al+3 ClO3 -1

3. Sr+2 SO4 -2

4. K+1 NO2 -1

5. Mg+2 PO4 -3

Going Backwards! Write the formula from the name of the ternary compound. Polyatomic ions, which have a negative charge generally, end in ITE or ATE. Hydroxide (OH-), cyanide (CN-), and peroxide (O22-) are the few polyatomic ions, which are exceptions.

Name Cation Anion Formulaex. Beryllium nitrite Be+2 (NO2)-1 Be(NO2)2

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1. Sodium hydroxide

2. Calcium sulfate

3. Potassium chromate

4. Gold (III) carbonate

5. **Ammonium perchlorate

** contains 2 polyatomic ions

X. Stoichiometry of FormulasStoichiometry means math relationship, in this case, involving chemical formulas.A. Smartie Moleculea) The smartie candy roll represents a molecule. The different colors of the individual candies represent different elements contain in the smartie molecule. List the colors contain in your molecule:

__________________________________________________________________The list of the different colors of the candies represents qualitative data. Qualitative data tells what elements are present in a formula.

b) Count the number of each individual color present in the smartie molecule and list them below in “ROYGBIVW” order.

__________________________________________________________________The list of the number of each different color of the candies in the smartie molecule represents quantitative data. Quantitative data tells how much of each element is present in a formula. Both the type and number of each element is told.

c) Identify the following statements as examples of quantitative or qualitative data._________________________The compound contains hydrogen and carbon atoms._________________________The compound contains 8 hydrogen and 4 carbon atoms.B. The MOLEa) Write the formula of your smartie molecule in “ROYGBIV” order using the number of each color as a subscript (ex. R3O4....) ____________________________________b) How many total “atoms” are present in ONE smartie molecule? _____________

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(Count up the subscripts)

c) Molecules are too small a unit to count in chemistry. We use the unit called the mole to count in chemistry. One mole of atoms is equal to 6.02 x 1023 atoms; one mole of molecules is equal to 6.02 x 1023 molecules, etc.1 mole of smartie molecules = ______________________________ smartie molecules. 2 moles of smartie molecules = 2 x (6.02 x 1023) = 1.20 x 1024. Since counting in moles (1,2,3 etc) is so much easier than in molecules (multiples of 6.02 x 1023), this is what we will use. Since one smartie molecule contains _________________“atoms”, one mole of smartie molecules will contain the same number of moles of atoms: ______________________.

d) Counting moles of atoms in a formulaFor 1 mole of each of the following compounds, determine the number of moles of each element is present and the total number of moles of atoms present:ex.: KBr: 1 mole K & 1 mole Br ; total moles = 2 moles

Li2O: 2 moles Li & 1 mole O ; total moles = 3 molesWhen parenthesis are used, multiply the number of each element inside the parenthesis by number on the outside the parenthesis:

Sr(NO3)2 Sr = 1 mole; N = 2x1= 2 moles; O = 3x2=6 molestotal moles of atoms = 1 mole + 2 moles + 6 moles = 9 moles

Al (NO3)3

Mg3(PO4)2

K2SO4

CaCl2

NaClTotal moles presentNumber of moles of each elementCompound

C. How do you measure moles? With a balance!a. One mole of an element is equal to the atomic mass of that element in grams. This is called the gram formula mass (GFM). Simply, look up the atomic mass of the element and place the unit, grams per mole (g/mole), after the number. To make life easier, round off the atomic mass to the tenths place. Example: chlorine; Cl use 35.5 g/mole. For carbon (C), look up the atomic mass of C, it is 12.0 amu so 1 mole of C will have a mass of 12.0 g/mole.Determine the gram formula mass of the elements given (Don’t forget the units):

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AlOS

MgFe

CaNBrCu H

GFMElementGFMElement

b. Gram Formula Mass of CompoundsSince one mole of an element is the atomic mass in grams , the GFM of a compound is the sum of the GFM of the elements of the atoms in the compound.KBr K = 39.1 g/mole; Br =79.9 g/mole GFM= (39.1 + 79.9.)g/mole = 119.0 g/moleLi2O Li = 6.9 g/mole; O = 16.0 g/mole Since there are 2 Li, you must multiply

the GFM of Li by 2: GFM = [2(6.9) + 16.0] = 29.8 g/moleSr(NO3)2 Sr = 87.6 g/mole; N = 14.0 g/mole; O = 16.0 g/mole Again, you

must multiply individual GFM by the number of each element present.GFM = [87.6 + 2(14.0) + 6(16.0)] g/mole = 211.6 g/mole.

Remember to show units & work! Units are g/ mole. NO Work NO CREDIT!!!!

1) NaCl 5) Na2SO4

2) NaOH 6) ZnSO4

3) Mg(OH)2 7) Th(NO3)4

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4) KNO3 8) CH3Br

C. Special Formulas: HydratesHydrates are ionic compounds that have certain number of moles of water trapped in the crystal structure of 1 mole of the hydrate. Gypsum drywall used in the construction of homes is a hydrate of calcium sulfate. The trapped water in the drywall adds to the fire protection provided by walls constructed of drywall. The formula of gypsum drywall is CaSO42H2O. This means it’s a hydrate. It DOES NOT mean to multiply as it does in math class. Two moles of water are trapped for every one mole of CaSO4. To calculate the GFM of the hydrate, the GFM of the ionic compound is added to the number of moles of water times the GFM of the water.GFM of CaSO42H2O = GFM of CaSO4 + 2 x GFM of H2OGFM CaSO42H2O = [40.1 +32.1+ 4(16.0)]g/mole +2 [2(1.0)+16.0] g/mole

= 172.2 g/moleSince there are 2 moles of water trapped in the CaSO42H2O, the GFM of water is multiplied by 2.What is the GFM of CoCl26H2O ?GFM of CoCl26H2O = GFM of CoCl2 + 6 x GFM of H2OSince the GFM of H2O is 18.0 g/mole, you can substitute that value in rather than figure it out each time.GFM of CoCl26H2O = [58.9 + 2(35.5)] g/mole + 6 (18.0g/mole) =237.9 g/moleSince there are 6 moles of water trapped in the CoCl26H2O, the GFM of water is multiplied by 6.Remember to show units & work! NO Work NO CREDIT!!!!1) CuSO45 H2O 2) Na2CO310 H2OGfm of CuSO4 5 x Gfm of H2O Gfm of Na2CO3 ___ x Gfm of H2O

Gfm CuSO4 + (5 x Gfm H2O) = gfm hydrate

Gfm Na2CO3 +(__xGfm H2O) = gfm hydrate

3) MgSO410 H2O 4) BaCl22 H2OGfm of MgSO4 __ x Gfm of H2O Gfm of BaCl2 __ x Gfm of H2O

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Gfm MgSO43 +(__xGfm H2O) = gfm hydrate

Gfm BaCl2 +(__xGfm H2O) = gfm hydrate

IV. Mole Calculations: Calculating Moles From GramsWhat is the formula on Ref. Table T for mole calculations? ______________________Step 1: Calculate the GFM of the compound given.Step 2: Plug the numbers with units in the formula from ref table T. The grams you are given are always put “on top,” and the GFM on the bottom.ex: How many moles of H2O are in 9.0 g?Step 1: gfm of H2O = 2(1.0) +16.0 g/mole = 18.0 g/moleStep 2: mole of of H2O = 9.0 g/18.0 g/mole = 0.50 moles (2 sig figs needed)

Calculate the number moles of each compound contained in the grams that are given.Remember to show formula, units & work! NO Work NO CREDIT!!!! (Remember to use thegfm of the compound you are given!!) Circle answer.NO WORK, NO CREDIT !! NO credit for just answers!!!1) 72 grams of H2OStep 1: GFM: Step 2: # moles:

2) 29.25 grams NaClStep 1: GFM: Step 2: # moles:

3) 60. grams of NaOH

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Step 1: GFM: Step 2: # moles:

4) 71 grams of Na2SO4Step 1: GFM: Step2: # moles:

5) 15.75 grams of HNO3Step 1: GFM: Step 2: # moles:

V. Calculating Grams from MolesTo calculate the grams from moles, rearrange the formula given for mole calculations by solving for grams. The TRIANGLE can be used to help rearrange the formula:

Step 1: Calculate the GFM of the compound given.Step 2: Plug the numbers with units in the rearranged formula from ref table T. The units should cancel out leaving only grams.Hint to remember: You “MOLETIPLY” to get grams. (Groan all you want!)ex. How many grams of water are in 2.5 moles?Step 1: gfm of H2O = 2(1.0) +16.0 g/mole = 18.0 g/moleStep 2: # grams = (2.5 moles)(18.0 g/mole) = 45 gRemember to show formula, units & work! NO Work NO CREDIT!!!! (Remember to use the gfm of the compound you are given!!) circle final answer

How many grams are present in the moles of each compound given?1) 2.00 moles of AlF3

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Step 1: GFM: Step 2: # grams:

2) 10.0 moles of NaClStep 1: GFM: Step 2: # grams:

3) 2.50 moles of Mg(OH)2Step 1: GFM: Step 2: # grams:

4) 0.50 moles of CH3BrStep 1: GFM: Step 2: # grams:

5) 4.00 moles of H2SO4Step 1: GFM: Step 2: # grams:

VI: Percent Composition:What is the formula on Ref. Table T for Percent Composition?

Model for % Composition: How much sugar is there in bubble gum????

What type of data do we need? ____________________________________

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How can you remove the sugar? ____________________________________

Data:

A. Percent Composition when data is given in grams. In lab, the data recorded will be in grams. To determine the percent of an element in a compound, plug the grams of the “PART” (ELEMENT YOU WANT) over the MASS of the whole compound.example: In the analysis of water, 2.00 g of hydrogen was collected from 18.0 g of water. What is the mass percent of hydrogen in water.

%mass H = (2.00g/18.0g) x 100 = 11.1% Note: units must be the same in order to cancel out, there are no units to a percentRemember to show units & work! NO Work NO CREDIT!!!!

1. Carbon monoxide (CO) was analyzed to contain 6.0 g carbon in a 14 g sample of CO.What is the percent C in the sample?Math Formula Numbers & units plugged in

Unrounded answerAnswer with unit (%) rounded to proper sig figs

2. A 250. g sample of Cu2S contains 50.0 g of S. What are the percent S ?and percent Cu in the compound?Math Formula Numbers & units plugged in

Unrounded answerAnswer with unit (%) rounded to proper sig figs

How would you get the percent Cu in the compound?

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3. A hydrate was heated to remove the trapped water. If 3.600 g of water was removed from 10.000 g the hydrate, what is the percent water? (here, water is the part and the hydrate is the whole)Math Formula Numbers & units plugged in

Unrounded answerAnswer with unit (%) rounded to proper sig figs

4. The usual form of a hydrate question is this: A 20.0g sample of a hydrate is heated until all the water is driven off. The mass of the anhydride compound (hydrate without the water) is 15.0 g. What is the % water? First you need calculate the difference in the two masses to get the grams of water removed, then proceed as in #3 above.

Math Formula Numbers & units plugged in Unrounded answer

Answer with unit (%) rounded to proper sig figs

5. Calculate your % sugar (on page 18) when the “taste” is gone from the gum. Math Formula Numbers & units plugged in

Unrounded answerAnswer with unit (%) rounded to proper sig figs

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How is calculating the % sugar in bubble gum similar to the percent water in a hydrate calculation?

__________________________________________________________________

B. Percent Composition when data is a formula.

Here you use the GFM of the compound for the whole and the GFM of the element times its subscript for the part.

What is the % of H and C in CH4?GFM of CH4 = [12.0 + 4(1.0)]g/mole = 16.0 g/moleGFM of H = 4(1.0) g/mole = 4.0 g/mole (remember there are 4 H)%mass H = (4.0g/mole/16.0 g/mole) x 100 = 25%

To get % C you repeat the step above % C = (12.0 g/mole/16.0 g/mole) x 100 = 75.0%

or subtract 25% from 100%.Note: Because of rounding off, it is not unusual for the sum of the individual percents to range from 99% to 101%.Remember to show units & work! NO Work NO CREDIT!!!! Calculate the percent of each element 1) WO3GFM: % W =

% O =

2) MgCl2GFM: % Mg =

% Cl =

3) Na2CO3

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GFM: % Na =

% C =

% O =

4) KClO3GFM: % K =

% Cl =

% O =

5) Mg(NO3)2GFM: % Mg =

% N =

% O =

C. Percent Water in a Hydrate (p14 has the steps for gfm of whole hydrate)% water = (part water/ whole hydrate) x100 % water = { [# water x (gfm of water)]/ gfm of the hydrate} x 100ex.: What is the % water in CaSO42H2O ?Part water = 2 x gfm of water = 2 [2(1.0) +16.0] g/mole = 36.0 g/moleWhole is the gfm of CaSO42H2O:GFM ofCaSO42H2O = [40.1 +32.1 4(16.0)]g/mole +2 [2(1.0)+16.0] g/mole

= 172.2 g/mole% water = (36.0 g/mole/172.2 g/mole) x 100 = 20.9%Remember to show units & work! NO Work NO CREDIT!!!! 1. What is the % water in CuSO45H2O ?

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# H2O x GFM of H2O:

GFM of Whole hydrate:

% H20 =

2. What is the % water in BaCl22 H2O ?# H2O x GFM of H2O:

GFM of Whole hydrate:

% H20 =

3. What is the % water in CoCl26H2O?

# H2O x GFM of H2O:

GFM of Whole hydrate:

% H20 =

V. Density of Gasses at STP: From unit on the gas laws, we will learn that all gases at the same temperature, pressure and volume have the same number of molecules. At STP (standard temperature and pressure) 1 mole of any gas has a volume of 22.4 L. We can use this volume to calculate the density of any gas. Since 1 mole of a gas is its gram formula mass (GFM), we can use GFM of the gas for the mass and 22.4 L for volume in the density formula. We can also determine the GFM of an unknown gas at STP if we know its density since its volume will be 22.4 L!

Look up on ref table T the density formula and write it below.

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Example: What is the density of hydrogen gas (H2) at STP?

Step 1: Calculate the GFM

Gfm= 2(1.0) = 2.0 grams

(the moles would cancel out later, so just use grams instead of g/mol)

Step 2: Use the density FormulaVolume at STP = 22.4 L/molD = 2.0 g/ 22.4 L = 0.089285714 g/L

D = 0.089 g/L

(the moles would cancel out later, so just use Liters instead of L/mol)

1) What is the density of chlorine gas (Cl2) at STP?Step 1: Calculate the GFM Step 2: Use the density Formula

Volume at STP = 22.4 L

2) What is the density of fluorine gas (F2) at STP?

Step 1: Calculate the GFM Step 2: Use the density FormulaVolume at STP = 22.4 L

3) What is the density of methane gas (CH4) at STP?Step 1: Calculate the GFM Step 2: Use the density Formula

Volume at STP = 22.4 L

4) What is the density of ammonia gas (NH3) at STP?Step 1: Calculate the GFM Step 2: Use the density Formula

Volume at STP = 22.4 L

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Rearranging the density formula, can allow you to calculate the gram formula mass of an unknown gas. The volume is still 22.4 L and the density is given. In the following problems you will solve for the mass in the density equation.5) What is the gram formula mass of an unknown gas whose density at STP is 1.96 g/L ?Step 1: Rearrange the density formula to solve for mass.

Step 2: Use this rearranged formula to solve for mass.Volume at STP = 22.4 L

6) The density of a Noble Gas at STP is 5.86 g/L. What is its gram formula mass and identity? Step 1: Rearrange the density formula to solve for mass.

Step 2: Use this rearranged formula to solve for mass.Volume at STP = 22.4 L

Step 3: Look up on the PT !

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