Ch.4 - Chemical Quantities & Aqueous ReactionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Jules Bruno

Calculating oxidation number

Redox reactions involve a reactant being oxidized while another reactant is reduced. But in order to understand who’s been oxidized and who’s been reduced, you first must master calculating the oxidation numbers of compounds as well as elements. Without being able to do this, you won’t know for sure who’s been oxidized and who’s been reduced. When we talk about calculating the oxidation number, we break it down into two categories. We have our general rules and we have our specific rules. 

How to calculate oxidation number 

When it comes to general rules, we’re talking about calculating the oxidation number of an entire element or a compound. 

For an atom in its elemental form, the oxidation number will equal to zero. When we say elemental form, that means that the element is either by itself like we have a carbon (solid), or it’s connected to copies of itself like Cl2, P4 and S8. This is also important. Not only does the element need to be either by itself or with copies of itself, but it must not have any charge present. They must be neutral. If that’s true, then its oxidation number will be zero. Each of these have an oxidation number of zero. 

For an ion, the oxidation number equals the charge. Here, oxygen is by itself but it has a charge so its oxidation number now is -2. Sodium here, its oxidation number is equal to its charge so it’d be +1. Here phosphate, the entire polyatomic ion has an oxidation number of -3. Then finally, ammonia, if we’re looking at the entire compound, its oxidation number is equal to 0 because it has no charge present. 

When we talk about specific rules, that’s when we’re talking about finding the individual oxidation numbers of elements within a molecule or compound.

If we have a Group 1A ion that’s part of a compound, its oxidation number is +1. If we have a Group 2A element within a compound, its individual oxidation number is +2. Then things start to get a little bit different from what we’re accustomed to seeing with charges.

Oxidation number of hydrogen 

Here for hydrogen, it is +1 when it’s connected to nonmetals. Here, hydrogen is connected to oxygen so it’s +1, it’s still +1 (NH3), and here it’s +1 (HBr). But once that hydrogen connects to a metal or to boron, its oxidation now becomes -1. In these cases, hydrogen is connected either to a metal or to a boron. 

Oxidation number of fluorine

When we look at Fluorine within a compound, It doesn't care what’s around it. If fluorine is within a compound, its individual oxidation number will always be -1.

Oxidation number of oxygen

With oxygen, it gets a little bit crazier. 


With oxygen, if it’s a peroxide, it’s gonna be -1 for its oxidation number. A peroxide has the formula of X2O2, where X represents a Group 1A element. Here we have hydrogen peroxide, sodium peroxide and potassium peroxide. Notice the setup. It’s two elements from Group 1A connected to two oxygens. That’s what makes a peroxide. 

If it’s a superoxide, its oxidation number will be -½. What’s the general setup of a superoxide? A superoxide is just one element from Group 1A connected to two oxygens. Remember, X represents a Group 1A element. Here we have potassium superoxide, cesium superoxide and lithium superoxide. In these cases, oxygen would be -½.

If oxygen is not in a peroxide or a superoxide, then its oxidation number will equal -2.

Oxidation number of halogens

Finally, halogens, which are elements in Group 7A. They are -1 except when they’re connected to oxygen. 

When they’re connected to oxygen, we don’t know what their new oxidation number will be. We will have to calculate it. The exception to this is go back to fluorine. Fluorine doesn't even care if it’s connected to oxygen. It’s still always gonna be -1 when it’s within a compound. 

Summary

Again, it’s essential that you learn these rules for calculating the oxidation number of compounds as a whole as well as individual elements within a compound. This is the first step to really understanding redox reaction. It’s highly suggested that you memorize these rules. Then when we talk about redox reactions, remember the fundamental features of oxidation versus reduction.


Jules Bruno

Jules felt a void in his life after his English degree from Duke, so he started tutoring in 2007 and got a B.S. in Chemistry from FIU. He’s exceptionally skilled at making concepts dead simple and helping students in covalent bonds of knowledge.


Additional Problems
What are the oxidation numbers of chlorine on the reactant side and on the product side in the following redox reaction? 2 OH - (aq)  +  Cl2O7 (g)  +   4 H2O2 (aq)  →  2 ClO2 - (aq)  +   4 O2 (g)  +   5 H2O (l)  A. Reactant: –1; product: +3 B. Reactant: +7; product: +3 C. Reactant: +14; product: –1 D. Reactant: +7; product: +4 E. Reactant: 0; product: –1
In which molecule below is the oxidation number of oxygen  not - 2? (1) ClO2–         (2)  O2       (3)  Na2O2   a. (1) and (2) only b. (1) and (3) only c. (2) and (3) only d. only (1) or only (2) or only (3) e. (1) and (2) and (3)  
What is the oxidation number of each atom in ammonium hydrogen phosphate, (NH4)2HPO4?  a. N = -3, H = +1, P = +5, O = –2 b. N = +3, H = +1, P = +5, O = –2 c. N = +4, H = +1, P = +6, O = –2 d. N = –3, H = +1, P = +8, O = –2 e. N = -3,  H = -1,  P =+8,  O = -2  
What is the oxidation number of carbon in HCO 3-? A. -2 B. +1 C. -4 D. +4 E. +5
What is the oxidation number for C in the chemical compound CaCO 3. a. +3 b. +6 c. +4 d. +2 e. -4
What is the oxidation number of sulfur in H2S2O7? A. +6 B. +12 C. -2 D. -4
What is the oxidation number of sulfur in SO  42−? 
What is the oxidation number of chlorine in HClO 3? a) +3 b) -1 c) -3 d) +5 e) +7
Assign the oxidation numbers to the following for Dinitrogen pentoxide: N :______ O: ______
Fluorine reacts with cold sodium hydroxide solution to produce oxygen difluoride as shown in the following chemical equation 2 F2 (g) + 2 NaOH (aq) → 2 NaF (aq) + H 2O (l) + OF2 (g) Assign the oxidation numbers for the atoms in reactants an products of this reaction listed below.    
Determine the oxidation state of P in PO33-. A) +3 B) +6 C) +2 D) 0 E) -3
What is the oxidation number of sulfur in SO42-?
In which pair does the named element have the same oxidation number? (A) sulfur in H2S2O7 and in H2SO4 (B) mercury in Hg2+ and in Hg 22+ (C) oxygen in Na2O2 and in H2O (D) cobalt in Co(NH3)63+ and in Co(NO3)2
In which compound does vanadium have the lowest oxidation state? (A) V2O5 (B) V2O3 (C) VO2 (D) VO
What is the oxidation number of chromium in Na 2Cr2O7? (A) +12 (B) +6 (C) +3 (D) -2
What is the oxidation number in H 2C2O4? a) +3 b) +4 c) +6 d) +8
In which compound does vanadium have the LOWEST oxidation state?   A. V2O5 B. V2O3 C. VO2 D. VO
The oxidation number of sulfur in the compound (NH 4)2SO4 is: a) -3 b) -1 c) +2 d) +4 e) +6
If the following compound were formed from an iron atom combining with a nitrate ion: Fe(NO3)53-, what would be the oxidation number of the iron atom?  a) +1 b) +2 c) +5 d) -2
Some of the known Phosphorous oxoacids are the following, list the oxidation state for phosphorous. H3PO4 H3PO2 H5P3O10 H4P2O7
In which compound is the oxidation state of oxygen not –2?      A) Al2O3      B) Li2O      C) K2O2      D) MgO           E) CO
In which of the following is the correct oxidation number for nitrogen given? (A) HNO3, +4 (B) NO2, +2 (C) NCl3, –3 (D) N2, –1 (E) None of the above
Consider the chemical reaction: 2 SO 2 (g) → SO(g) + SO3 (g) Determine if the sentence below is true or false. The oxidation number of sulfur in SO 3 is +6.  
What is the oxidation number for chromium in the following compound? Cr2O72-
In which compound does bromine have the HIGHEST oxidation state? A) HBrO4 B) HBrO3 C) BrCl5 D) HBr
What is the oxidation number of phosphorus in H 3PO2? A. +1 B. +2 C. +3 D. +4
Give the oxidation number of the underlined atom in the following molecules and ions: a) Mn(NH3)3 2+                                     b) (NH4)2C2O4  
If the following compound where formed from an iron atom combining with a nitrate ion: Fe(NO3)53- what would be the oxidation number of the iron atom?   a) + 1 b) + 2 c) + 5 d) – 2 
Give the oxidation numbers of the underlined atoms in the following molecules and ions: A) Mg3N2, B) CsO2, C) CaC2, D) CO32−, E) C2O42−, F) ZnO22−, G) NaBH4, H) WO42−.
Consider the complex ion [Fe(CN) 6] 4– . What is the oxidation number of the iron? a. +1 b. +2 c. –1 d. +5
Give the oxidation number of the underlined atom in the following molecules and ions: a) ClO4–                                                                                     d) SO32-       b) CrO4 –                                                                         e)        As2O72-
What are the oxidation numbers of carbon in CO 2, CH4 and C2H6? A. 4, 4, 4 B. 4, -4, 3 C. -4, 4, 3 D. 4, -4, -3 E. 4, -4, -4
Replacement of aluminum ions in kaolinite with magnesium ions yields a compound with the formula Mg3Si2O5(OH)4. Assign an oxidation state to each element in this compound.What is the oxidation state of Mg in Mg3Si2O5(OH)4?
Iron corrodes to produce rust, Fe2O3, but other corrosion products that can form are Fe(O)(OH), iron oxyhydroxide, and magnetite, Fe3O4.What is the oxidation number of Fe in iron oxyhydroxide, assuming oxygens oxidation number is -2?
Iron corrodes to produce rust, Fe2O3, but other corrosion products that can form are Fe(O)(OH), iron oxyhydroxide, and magnetite, Fe3O4.It turns out that there are two different kinds of Fe in magnetite that have different oxidation numbers. Suggest what these oxidation numbers are and what their relative stoichiometry must be, assuming oxygens oxidation number is -2.
Determine the oxidation number for the indicated element in each of the following substances.Mn in KMnO4
Magnesium, the element, is produced commercially by electrolysis from a molten salt (the "electrolyte") using a cell similar to the one shown below. What is the most common oxidation number for Mg when it is part of a salt?
Assign oxidation states to each atom in each of the following species.Ag+
Arsenic forms binary compounds with Cl and with Mg.Will it be in the same oxidation state in these two compounds?
Potassium superoxide, KO2, is often used in oxygen masks (such as those used by firefighters) because KO2 reacts with CO2 to release molecular oxygen. Experiments indicate that 2 mol of KO2 (s) react with each mole of CO2(g).Indicate the oxidation number for each atom involved in the reaction in part A. Before the reaction:
Potassium superoxide, KO2, is often used in oxygen masks (such as those used by firefighters) because KO2 reacts with CO2 to release molecular oxygen. Experiments indicate that 2 mol of KO2 (s) react with each mole of CO2(g).Indicate the oxidation number for each atom involved in the reaction in part A. After the reaction:
Figure: Representative oxidation states of the elements. Note that hydrogen has both positive and negative oxidation numbers, +1 and -1. The red stepped line divides metals from nonmetals. The red stepped line divides metals from nonmetals. How are common oxidation states divided by this line?
What are the oxidation numbers of the elements in the nitrite ion, NO2-?
Assign oxidation states to each atom in each of the following species.CaF2
Assign oxidation states to each atom in each of the following species.CrO4 2 -
What is the oxidation state of Cr in each of the following compounds?CrO
What is the oxidation state of Cr in each of the following compounds?CrO3
Elements in group 7A in the periodic table are the halogens; elements in group 6A are called the chalcogens.What is the most common oxidation state of the chalcogens compared to the halogens?
One of the key components in the manufacture of Portland cement is, Ca3SiO5, a compound that is obtained by firing the reactants in a kiln at 1400 - 1500 C. Assign an oxidation state to each element in this compound.What is the oxidation state of Si in Ca3SiO5?
Replacement of aluminum ions in kaolinite with magnesium ions yields a compound with the formula Mg3Si2O5(OH)4. Assign an oxidation state to each element in this compound.What is the oxidation state of O in Mg3Si2O5(OH)4?
Replacement of aluminum ions in kaolinite with magnesium ions yields a compound with the formula Mg3Si2O5(OH)4. Assign an oxidation state to each element in this compound.What is the oxidation state of H in Mg3Si2O5(OH)4?
Replacement of aluminum ions in kaolinite with magnesium ions yields a compound with the formula Mg3Si2O5(OH)4. Assign an oxidation state to each element in this compound.What is the oxidation state of Si in Mg3Si2O5(OH)4?
What is the oxidation number of nitrogen in nitric acid, HNO3?
You may want to reference (Pages 320 - 322) Section 8.6 while completing this problem.Assign oxidation numbers to each of the atoms O, C, and S in OCS.
Assign oxidation states to each atom in each of the following species.CO3 2 -
Determine the oxidation number for the indicated element in each of the following compounds: (b) Sn in SnCl3 -
Determine the oxidation number for the indicated element in each of the following compounds: (c) C in C2O42-
Determine the oxidation number for the indicated element in each of the following compounds: (d) N in N2H4
Determine the oxidation number for the indicated element in each of the following compounds: (e) N in HNO2
Determine the oxidation number for the indicated element in each of the following compounds: (f) Cr in Cr2O72-.
The oxidation number of nitrogen given for the following compounds is correct except for which one?a. hydrazine, N2H4 (-2)b. nitrous oxide, N2O (+1)c. hydroxylamine, NH2OH (-1)d. nitrous acid, HNO2 (+3)e. hydrazoic acid, HN3 (-1)
Assign oxidation states for all atoms in each of the following compounds.a. UO22+
Assign oxidation states for all atoms in each of the following compounds.b. As2O3
Assign oxidation states for all atoms in each of the following compounds.c. NaBiO3
Assign oxidation states for all atoms in each of the following compounds.d. As4
Assign oxidation states for all atoms in each of the following compounds.e. HAsO2
What is the oxidation state of an individual carbon atom in CaCO 3?
Assign oxidation states for all atoms in each of the following compounds.f. Mg2P2O7
Assign oxidation states for all atoms in each of the following compounds.g. Na2S2O3
What is the oxidation state of each element in Mn(ClO 4)3? 
Assign oxidation states for all atoms in each of the following compounds.h. Hg2Cl2
Order the following molecules from lowest to highest oxidation state of the nitrogen atom: HNO3, NH4Cl, N2O, NO2, NaNO2.
Assign oxidation states for all atoms in each of the following compounds.i. Ca(NO3)2 
Assign the oxidation state for nitrogen in each of the following.a. Li3N
Assign the oxidation state for nitrogen in each of the following.b. NH3
Assign the oxidation state for nitrogen in each of the following.c. N2H4
Assign the oxidation state for nitrogen in each of the following.d. NO
Assign the oxidation state for nitrogen in each of the following.e. N2O
In which species does sulfur have the lowest oxidation state? a) SCI2 b) OSF2 c) H2SO3 d) SF6
Assign the oxidation state for nitrogen in each of the following.f. NO2
Assign the oxidation state for nitrogen in each of the following.g. NO2–
Assign the oxidation state for nitrogen in each of the following.h. NO3–
Assign the oxidation state for nitrogen in each of the following.i. N2
Which species has an atom with an oxidation number of +3? a) CIO2– b) PO43– c) S2O32– d) NO2+
Assign oxidation numbers to all the atoms in each of the following.a. SrCr2O7
Assign oxidation numbers to all the atoms in each of the following.b. CuCl2
Assign oxidation numbers to all the atoms in each of the following.c. O2
Assign oxidation numbers to all the atoms in each of the following.d. H2O2 
What is the oxidation state of Cl in each of the following ions?a. ClO-b. ClO2-   c. ClO3-d. ClO4-
Assign oxidation numbers to all the atoms in each of the following.e. MgCO3
Assign oxidation numbers to all the atoms in each of the following.f. Ag
what is the symbol for carbon? what is the atomic number of it in the periodic table ? how many protons and electrons in the atom of carbon? give the highest possible and lowest possible oxidation state for carbon? determine it molar mass?
Assign oxidation numbers to all the atoms in each of the following.g. PbSO3
Assign oxidation numbers to all the atoms in each of the following.h. PbO2
Assign oxidation numbers to all the atoms in each of the following.i. Na2C2O4
Assign oxidation numbers to all the atoms in each of the following.j. CO2
Determine the oxidation state of all the elements in the following compounds.F3NbO H2SO3 PH3
Assign oxidation numbers to all the atoms in each of the following.k. (NH4)2Ce(SO4)3
Assign oxidation numbers to all the atoms in each of the following.l. Cr2O3
Determine the oxidation number (oxidation state) of each element in the following six compounds.a. CuCO3b. CH4c. IF d. CH2Cl2 e. SO2f. (NH4)2CrO4
What is the oxidation state of each element in Mn(NO 3)2?
What is the oxidation number of oxygen atom in O 22– ? A) +1 B) –2 C) +2 D) –1
What is the oxidation state of each element in COH 2?
Differentiate between the following terms.c. oxidation state versus actual charge
Choose the INCORRECT statement:a. If reactants are not in stoichiometric ratio some will always be left at the completion of the reaction.b. The oxidation number of an atom is always an integer.c. The percent yield is the ratio of the actual to theoretical yield times 100.d. One mole is equivalent to 12 amue. None of the above
What is the oxidation state of an individual nitrogen atom in KNO 3? What is the oxidation state of each individual carbon atom in C2O4-2? 
What is the oxidation state of an individual:carbon atom in CaCO3?nitrogen atom in KNO3?phosphorus atom in PO43−?carbon atom in C2O42−?Express the oxidation state numerically (e.g., +1).
The oxidation number of the oxygen atom in F 2O is: a. -2 b. -1 c. +2 d. +1 e. 0
Determine the oxidation state of S in MgSO4.  a. -4 b. +2 c. +4 d. +6 e. -2
Classify each of the following binary compounds by the oxidation number of oxygen.CaOK2OK2O2KO2O2CO2CaO2O3
A piece of metal was placed in a beaker, heated, and reacted with oxygen, thereby becoming a metal oxide. During this process, depending on reaction conditions, the metal’s oxidation state could become either M2+ or M3+. Consider the mass of the metal oxide. a) The mass of the metal oxide is the same as the mass of the initial metalb) The mass of the metal oxide is greatest if the metal becomes M 3+c) The mass of the metal oxide is greatest if the metal becomes M 2+d) The mass of the metal oxide is greatest if O 2(g) is the limiting reactant. 
What is the oxidation number of chromium in Cr 2O72-?      A) +2      B) -3      C) +3      D) +4      E) +6
What is the oxidation state of each element in Mn(CrO 4)2?
The elements X, Y, and  Z  form these compounds: XCl4, XZ2, YO. What formula would you predict for the compound formed between Y and Z? Assume normal oxidation states for chlorine and oxygen.a) YZb) YZ2c) Y2Zd) YZ3
What is the oxidation state of an individual nitrogen atom in NH 4OH?
What is the oxidation state of an individual nitrogen atom in HNO 3? Express the oxidation state numerically (e.g., +1).
The compound KI3 is formed when potassium iodide is mixed with elemental iodine (I2). It contains the polyatomic triiodide ion (I3–). There is something strange about the oxidation state of iodine in KI3. Use what you’ve learned to:a. Calculate the oxidation state on iodine, and explain how it is strange.b. Do you think the value you got is plausible for the OS of iodine in this substance? Explain.
What is the oxidation state of each individual carbon atom in C 2O42−? Express the oxidation state numerically (e.g., +1).
What is the oxidation number of manganese in MnO 4– ? 
Determine the oxidation state of P in PO33-. A) +6 B) +3 C) 0 D) +2 E) -3
a. What is the oxidation state of each element in K 2Cr2O7?b. What is the oxidation state of each element in SO 32-?
The oxidation state of vanadium in Rb4NaHV10O28 is: A) -6   B) +8   C) -5   D) +3   E) +5
Of the first atoms in each of the following formulas, which one has the highest oxidation number? A) CO3 2- B) NO3-  C) SO3  D) ClO3-  E) P2O5
What is the oxidation number of the sulfur atom in H2SO4? A) +4 B) +2 C) -2 D) +6
Determine the oxidation number for the indicated element in each of the following substances: (a) S in SO2
What is the oxidation state of an individual nitrogen atom in HNO 3?
Determine the oxidation number for the indicated element in each of the following substances: (b) C in COCl2
What is the oxidation state of an individual phosphorus atom in PO 33−?
Determine the oxidation number for the indicated element in each of the following substances: (c) Mn in MnO4-
Determine the oxidation number for the indicated element in each of the following substances: (d) Br in HBrO
Determine the oxidation number for the indicated element in each of the following substances: (e) As in As4
Determine the oxidation number for the indicated element in each of the following substances: (f) O in K2O2
Determine the oxidation number for the indicated element in each of the following compounds: (a) Ti in TiO2
Give the Oxidation state for each metal species. Fe → Fe(CO)5 → Fe(CO)4I2  
a. What is the oxidation state of an individual bromine atom in NaBrO 3? b. What is the oxidation state of an individual nitrogen atom in NH 2OH? c. What is the oxidation state of an individual sulfur atom in SO 42-? d. What is the oxidation state of each individual carbon atom in C 2O42-? Express the oxidation state numerically (e.g., +1).
Assign oxidation states to each atom in each of the following species: Ag, Ca2+, BaO, H2S, NO3-, CrO42-
What is the oxidation state of aluminum in the compound aluminum oxide? 
Assign oxidation states to each atom in each of the following species. Li+, CuCl2, CO, MnO4-, HCO3-,  
What is the oxidation state of an individual nitrogen atom in NH 4OH? Express the oxidation state numerically (e.g., +1).
Determine the oxidation number (oxidation state) for the indicated element in each of the following compounds.Co in LiCoO2
Determine the oxidation number (oxidation state) for the indicated element in each of the following compounds.Al in NaAlH4
Give the oxidation number of arsenic in each of the following:AsH3 
Give the oxidation number of arsenic in the following:H2AsO4 −
Give the oxidation number of arsenic in each of the following:AsCl3
Give the oxidation number of chromium in each of the following:Cr2(SO4)3
Which statement best describes the difference between the charge of a polyatomic ion and the oxidation states of its constituent atoms? (For example, the charge of NO3– is 1-, and the oxidation states of its atoms are +5 for the nitrogen atom and -2 for each oxygen atom.)(a) The charge of a polyatomic ion is a property of the entire ion, while the oxidation states are assigned to each individual atom.(b) The oxidation state of the ion is the same as its charge.(c) The charge of a polyatomic ion is not a real physical property, while the oxidation states of atoms are actual physical properties.
Determine the oxidation states of the elements in the following compounds:(b) GdCl3
Determine the oxidation states of the elements in the following compounds:(c) LiNO3
Determine the oxidation states of the elements in the following compounds:(f) RbO2, rubidium superoxide
Assign oxidation states for all atoms in NiO 2.
Assign an oxidation state to each atom in each species.(a) Cr(b) Cr3+(c) CCl4(d) SrBr2(e) SO3(f) NO3–
Assign oxidation states for all atoms in NaBiO 3.
Assign oxidation states for all atoms in Hg 2Cl2.
Identify the elements that undergo changes in oxidation number in the following reaction:2PbO2(s)  →  2PbO(s) + O2(g)
Identify the elements that undergo changes in oxidation number in the following reaction:2H2SO4(aq) + 2NaBr(s)  →  Br2(l) + SO2(g) + Na2SO4(aq) + 2H2O(l)
Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or superoxides.(b) Al(OH)3
Assign the oxidation state for the element listed in each of the following compounds:
Assign oxidation states for all atoms in (NH 4)2Ce(SO4)3.
What is the oxidation state of Cr in each of the following compounds?Cr2O3
Assign oxidation states to each atom in each of the following species.Cl2
Give the oxidation number of carbon in each of the following:CF2Cl2
Give the oxidation number of carbon in each of the following:HCO3 −
Give the oxidation number of bromine in each of the following:KBr
Give the oxidation number of bromine in each of the following:BrF3 
Give the oxidation number of bromine in each of the following:HBrO3 
Give the oxidation number of nitrogen in each of the following:N2F4 
Give the oxidation number of nitrogen in each of the following:HNO2
Give the oxidation number of sulfur in each of the following:SOCl2
Give the oxidation number of sulfur in each of the following: H2S2
Give the oxidation number of sulfur in each of the following:H2SO3
Give the oxidation number of sulfur in each of the following:Na2S
Give the oxidation number of phosphorus in each of the following:PCl5
Assign oxidation states for all atoms in P4O6.
Assign oxidation states for all atoms in XeOF4.
Assign oxidation states for all atoms in SF4.
Assign oxidation states for all atoms in C6H12O6.
Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or superoxides.(a) H3PO4
Assign oxidation states for all atoms in As 4.
Determine the oxidation number of sulfur in each of the following substances:barium sulfate, BaSO4
Determine the oxidation number of sulfur in each of the following substances:sulfurous acid, H2SO3
Assign the oxidation state for nitrogen in Li 3N.
Determine the oxidation number of sulfur in each of the following substances:strontium sulfide, SrS
Determine the oxidation number of sulfur in each of the following substances:hydrogen sulfide, H2S
Assign the oxidation state for nitrogen in N 2H4.
Determine the oxidation states of the elements in the compounds listed. None of the oxygen-containing compounds are peroxides or superoxides.(c) SeO2
Assign the oxidation state for nitrogen in NO 2.
Assign the oxidation state for nitrogen in NO 2-.
Assign the oxidation state for nitrogen in NO 3-.
The hypochlorite ion, ClO–, is the active ingredient in bleach. The perchlorate ion, ClO4−, is a main component of rocket propellants. What is the oxidation number of Cl in the perchlorate ion, assuming the Cl-O bonds are all single bonds?
The hypochlorite ion, ClO–, is the active ingredient in bleach. The perchlorate ion, ClO4−, is a main component of rocket propellants. What is the oxidation number of Cl in the hypochlorite ion ClO–?
What is the oxidation state of Cl in each of the following ions?ClO–
What is the oxidation state of Cl in each of the following ions?ClO2–
What is the oxidation state of Cl in each of the following ions?ClO3–
In the following reaction, the oxidation state (number) of chlorine changes from:2 Cr(OH)4-(aq) + ClO-(aq) + 2 OH-(aq) → 2 CrO42-(aq) + 3 Cl-(aq) + 5 H2O(I)A. -1 to -2B. +3 to +6C. +4 to +8D. +1 to -1E. -4 to +3
What is the oxidation number of phosphorus in  PO43−?
What are the oxidation numbers of 2Cl - and Cl2?
Determine the oxidation number of the highlighted atom in the following structure:
What is the oxidation number of carbon in the ion CO32-?
In which reaction does the oxidation number of hydrogen change?1) CaO(s) + H2O(l) → Ca(OH)2(s)2) 2Na(s) + 2H2O(l) → 2NaOh(aq) + H2(g)3) SO2(g) + H2O(l) → H2SO3(aq)4) HCl(aq) + NaOH(aq) → NaCl(aq) + H 2O(l)5) HClO4(aq) + CaCO3(s) → Ca(ClO4)2(aq) + H2O(l) + CO2(g)
How do you determine the oxidation number of nitrogen in the nitrate ion?
What is the oxidation number of N in N 2H4?
Using Lewis formulas, assign oxidation states to the atoms ina) H2CO (g)H =C =O =b) CH3OH (l)C =H =O =H =  (last H)
What is the oxidation number of manganese in Mn2O3?
What is the oxidation number of manganese in MnO2?
What is the oxidation number of Cl in perchloric acida. +7b. +5c. +1d. -1e. -5
Give the oxidation number of phosphorus in each of the following:H2P2O7 2− 
Which compound has the atom with the highest oxidation number?a. casb.na3nc. mgso3d. al(no2)3
What is the oxidation number of carbon in CO 2?
What is the oxidation number of Cl in Ba(ClO 2)2?
Place the following compounds in order of increasing oxidation state of nitrogen:NH2OH      N2H4      HNO2     NH+4      HNO3(A) HNO2 < NH2OH < N2H4 < HNO3 < NH+4(B) HNO3 < HNO2 < NH2OH < N2H4 < NH+4(C) NH+4 < N2H4 < NH2OH < HNO2 < HNO3(D) NH2OH < N2H4 < HNO2 < NH+4 < HNO3(E) N2H4 < NH+4 < HNO3 < NH2OH < HNO2
Determine the oxidation state (number) of bromine in BrO2- :A. -1B. 0C. +3D. +5E. +7
What is the oxidation number of the chromium atom in Na2CrO4 ?A) +7 B) +6 C) -2 D) +2
What is the oxidation number of SO 3?
What is the oxidation state of the carbon atom in the carbonate ion, CO 32-?
What is the oxidation state of an individual phosphorus atom in PO 33−? Express the oxidation state numerically (e.g., +1).
What is the oxidation state of each element in SO 32-?
What is the oxidation number of manganese in MnO 4-?
The substances NaF and CaO are isoelectronic (have the same number of valence electrons).What are the charges on each of the cations in each compound?
Give the oxidation state of the metal species in each complex.[Co(NH3)5Cl]Cl2 [Ru(CN)3(CO)2]3-
What is the oxidation state of each element in K 2Cr2O7?
Assign oxidation numbers to each element of the following equations.Ag(s) + CN-(aq) + O2(g) → Ag(CN)2-(aq) + H2O(l)NO2-(aq) + Al(s) → NH3(g) + AlO2-(aq)
What is the oxidation number of nitrogen in aluminum nitride, AlN?
Assign oxidation states for all atoms in HAsO2.
Assign oxidation states for all atoms in Na4Fe(OH)6.
Determine the oxidation number of Cl in each of the following species.1. Cl2O72. AlCl4-3. Ba(ClO2)24. ClF4+
For the following reactionKClO4 → KCl + 2O2assign oxidation states to each element on each side of the equation.
For the following reaction KClO4 → KCl + 2O2 assign oxidation states to each element on each side of the equation. 
What is the oxidation state of each element in FeBr 3?
What is the ionic charge of cobalt ion in [Co(en) 2(OH)2]Cl?
The total oxide ion charge in a formula unit of CoO is 2-. What is the charge on each cobalt ion?The total oxide ion charge in a formula unit of Co2O3 is 6-. What is the charge on each cobalt ion?The total oxide ion charge in a formula unit of CoO2 is 4-. What is the charge on each cobalt ion?
Determine the oxidation number (oxidation state) of EACH element in the following six compounds.a. CuCO3b. CH4c. IFd. CH2Cl2 e. SO2 f. (NH4)2 CrO4