Science Chemistry Chemical Bonds and Formulas Study Guide

What values do you see in a compound

- number of atoms of each element involved - formula mass - molar mass - % composition

The percent composition by mass of nitrogen in NH4OH (formula mass = 35 amu) is equal to?

14/35 x 100

A hydrate is a compound with water molecules incorporated into its crystal structure. In an experiment to find the percentage of water in the compound, the following data was recorded. Use the data and determine the percentage of water in the compound?

50 %

What is the percent by mass of oxygen in H2SO4 (formula mass = 98 amu)?

65%

What is the empirical formula of C6H12Cl2O2?

C3H6ClO

What is the molecular formula of a compound that has a formula mass of 54 amu and an empirical formula of C2H3?

C4H6

Which formulas could represent the empirical formula and the molecular formula of a given compound?

CH2 and C3H6

What is the empirical formula of C6H12O6?

CH2O

Which answer is both an empirical and molecular formula?

CH4

Which formula is an empirical formula?

CH4

How many atoms of each element are in the following compounds?

CH4: 1 Carbon and 4 Hydrogen Atoms Al2O3: Aluminum: 2, Oxygen 3 H3PO4: Hydrogen: 3, Phosphorus: 1, Oxygen: 4 HNO3: 1 Hydrogen, I Nitrogen, and 3 Oxygen Atoms

Name the following molecular compounds?

CO2: Carbon dixoide CCl4: Tetrachloromethane PCl5: Phosphorus Pentachloride SeF6: Selenium (VI) Fluorine As2O5: Arsenic (V) Pentoxide

What is the formula mass of CaCl2?

Ca: 40 Cl: 70 Grand Total: 110 amu

Give the formulas for the following compounds?

Carbon tetrabromide: CBr4 Silicon dioxide: SO4 Tetraphosphorus decoxide: P5O10 Diarsenic trisulfide: As2S3 Nitrogen trihydride: NH3

Write the formulas for the following combinations which involve a stock system ion?

Cr + F2+ : Chromium (II) Fluoride Ni2+ + O2- Nickel (I) Peroxide Fe3+ + O2-: Iron (III) Oxide

What is the molar mass of Cr(NO3)2?

Cr: 52 N: 28 O: 96 Grand Total: 176 amu

How to count Number of Atoms in Compound

Figure out what number is in subscript

Give the name of each of the following ionic compounds?

KCl: Potassium Chloride CaBr2: Calcium Bromide Li2O: Lithium Oxide MgCl2: Magnesium Chloride

Give the names of the following ionic compounds with polyatomic ions?

LiCrO4 Lithium Chromate (NH4)3PO4 Ammonium Phosphate KNO3 Potassium Nitrate NaOH Sodium Hydroxide

Cations for ionic bonds

Metals love to lose e- Located in Groups 1-13 When naming these cations we leave their names alone and simply copy them from the CRT Magnesium Lithium Aluminum Potassium

Examples of # of Atoms

NaCl = 1 sodium atom and 1 chlorine atom • MgI = 1 magnesium atom and 1 iodine atom • C2H6 = 2 carbon atoms and 6 hydrogen atoms • KNO3 = 1 potassium atom, 1 nitrogen atom and 3 oxygen atoms • Al2(SO4)3 = 2 aluminum atoms, 3 sulfur atoms, 12 oxygen atoms

Determine the percent composition of each element in each of the following compounds?

NaClO: Na: 23/178= 12.92% Cl: 35/178= 19.70% O: 16/178= 8.99%. H2SO3 : H: 2/82 = 2.44% S: 32/82 = 39.02% O: 48/82 = 58.54% C2H5COOH: C: 24/74= 32.40% H: 5/74= 6.76% C: 12/74= 16.22% O: 16/74= 21.62% O: 16/74= 21.62% H: 1/74= 1.35% BeCl2 : Be: 9/148= 6.08% CI: 70/148= 47.30%

Write the names of the ionic or covalent compounds listed below.

PbSO4 = Lead (II) Sulfate NH3 = Ammonium MgI2 = Magnesium Iodide NH4NO3 = Ammonium Nitrate CuBr2 = Copper (II) Bromide Ca(OH)2 = Calcium Hydroxide Pb(NO3)2 = Lead (II) Nitrate CaS = Calcium Sulfide NH4Cl = Ammonium Chloride NaHCO3 = Sodium Hydrogen Carbonate

Which compound has the highest percent composition by mass of strontium?

SrO

How to write formula for ionic bonded atoms with multiple charges

Step One: Evaluate and use Roman Numeral to Advantage Step Two: Write Charges, determine formula, and you are done

How to write the formula for Ionic bonded atoms

Step One: Write elements involved. Step Two: Check Charges and ask if they add up to 0. Step 3: If the answer is Yes, then combine and you are finished. Step 4: If the answer is No, Criss Cross numerical Values.

Determine the formula for the a compound consisting of 63.5% silver, 8.25% nitrogen, 28.25% oxygen?

The Formula is: AgNO3 63.5 g Ag1 mol107.90 g= 0.59 /0.59 = 1 8.25 g N1 mol14 g = 0.59/0.59 = 1 28.25 g O1 mol16 g= 1.76/0.59= 3

Polyatomic Ions Naming

Use Table E in CRT

Determine the molar mass and formula mass of each of the following compounds?

XeF4: Xe: 131.3 amu F: 76 amu. Formula Mass: 207.3 amu. Xe: 131.3 g/mol F: 76 g/mol. Molar Mass: 207.3 g/mol C12H24O6 C: 144 amu H: 24 amu O: 96 amu Formula Mass: 264 amu. C: 144 g/mol H: 24 g/mol O: 96 g/mol. Molar Mass: 264 g/mol Hg2I2 Hg: 400 amu I: 254 amu. Formula Mass: 654 amu. Hg: 400 g/mol I: 254 g/mol. Molar Mass: 654 g/mol CuCN Cu: 64 amu C: 12 amu N: 14 amu Formula Mass: 90 amu. Cu: 64 g/mol C: 12 g/mol N: 14 g/mol. Molar Mass: 90 g/mol

Calculate the percent composition of each element in ZnSO4 rounded to the hundredths place?

Zn: 65g/161g = 0.4037 x 100 = 40.37% S: 32g/161g = 0.1987 x 100 = 19.87%. O: 64g/161g = 0.3975 x 100 = 39.57%.

Write the formulas for each of the ionic or covalent compounds listed below.

aluminum iodide = AlI3 carbon dioxide = CO2 sulfur trioxide = SO3 hydrogen hydroxide = H2O boron sulfate = B2(SO4)3 sodium chloride = NaCl magnesium sulfate = MgSO4 iron (III) oxide = Fe2O3 sodium phosphate = Na3PO4 potassium sulfide = K2S

Give the formulas for the following combinations?

copper (I) chloride: Cu2+ + Cl- chromium (III) oxide: Cr2+ O3 gold (III) sulfide: Au2+ + S3-

What is one atom willing to lose in order to form that ionic bond

lose an e- while the other gains and e- (transfer e-)

What is an atom called when they lose electrons

lose or gain an e- that are no longer called atoms...now they are called ions

molecular vs empirical formula

molecular formula: actual formula of the compound empirical formula: formula showing the smallest whole-number ratio of the different atoms in the compound

What do specific chemicals need

need specific names that reveals specific information about the chemical

Anions for ionic atoms

nonmetals love to gain e- located in Groups 15-17 when naming these anions we need to change the end of their names so they end in -ide chloride sulfide bromide oxide

Give the formulas for the following compounds?

potassium permanganate: KMnO4 sodium hypochlorite: NaClO magnesium sulfate: MgSO4 calcium acetate: Ca(C2H3O2)2

Give the formula for the following ionic combinations?

sodium and iodine: NaI calcium and sulfur: CaS Li2O: Lithium Oxide barium and fluorine: BaF2

formula mass

sum of all the mass numbers of all atoms in its formula Uses amu (Atomic Mass Unit)

molar mass

sum of the mass numbers of elements present in a mole of that compound Same # as Formula Mass Uses g/mol unit

What happens when Ionic bonds are formed with Atoms

the atoms somehow make each other stable

What are many chemicals know by

their common names but this tells scientists little about its composition

Covalent Bonded naming

these molecules have shared e- so the names are based on prefixes

What do they do for each other by doing this

they help each other reach that stable octet of 8 valance e-

percent composition

useful to know the % of each element in a compound mass of the element / mass of the compound X 100 Round to the nearest tenths/hundredths, depending on what the question says

Examples of Covalent Bonding

• CCl4 = carbon tetrachloride • CO2 = carbon dioxide • N2O5 = dinitrogen pentoxide • NH3 = nitrogen trihydride