Worksheet: Chemistry Assignment 1— Name … Microsoft Word - 14-03 Chemistry Assignment 1 1401...
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Worksheet: Chemistry Assignment 1— Name___________________ Episode 1401 CHEMISTRY: A Study of Matter © 2004, GPB 14.3 Assign an oxidation number to each element: 1. H 2 2. H 2 O 3. NaF 4. Cl 2 5. H 2 SO 4 6. KClO 3 7. NH 3 8. Ba(OH) 2 9. AlBr 3 10. Mg
Transcript of Worksheet: Chemistry Assignment 1— Name … Microsoft Word - 14-03 Chemistry Assignment 1 1401...
Worksheet: Chemistry Assignment 1— Name___________________ Episode 1401
CHEMISTRY: A Study of Matter © 2004, GPB
14.3
Assign an oxidation number to each element: 1. H2
2. H2O
3. NaF
4. Cl2
5. H2SO4
6. KClO3
7. NH3
8. Ba(OH)2
9. AlBr3
10. Mg
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0 = all elements
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H=+1 O-2 Group 1 and Oxygen
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Na=+1 F-1 Group 1 +1 +F = 0
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H=+1 O-2 Group 1 and Oxygen SO4-2 S+-8=-2 S =+6
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0 = all elements
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0 = all elements
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K=+1 O-2 Group 1 and Oxygen ClO3-1 Cl +-6 =-1 Cl =-7
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H=+1 3(+1) +N = 0 N=-3
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Ba=+2 O-2 Group 2 and Oxygen OH-1 H +-2 = -1 H=+1
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Al=+3 3Br+3 = 0 Br =-1
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1. Free elements are assigned an oxidation state of 0. e.g. Al, Na, Fe, H2, O2, N2, Cl2 etc have zero oxidation states. 2. The oxidation state for any simple one-atom ion is equal to its charge. e.g. the oxidation state of Na+ is +1, Be2+, +2, and of F-, -1. 3. The alkali metals (Li, Na, K, Rb, Cs and Fr) in compounds are always assigned an oxidation state of +1. e.g. in LiOH (Li, +1), in Na2SO4(Na, +1). 4. Fluorine in compounds is always assigned an oxidation state of -1. e.g. in HF2-, BF2-. 5. The alkaline earth metals (Be, Mg, Ca, Sr, Ba, and Ra) and also Zn and Cd in compounds are always assigned an oxidation state of +2. Similarly, Al & Ga are always +3. e.g. in CaSO4(Ca, +2), AlCl3 (Al, +3). 6. Hydrogen in compounds is assigned an oxidation state of +1. Exception - Hydrides, e.g. LiH (H=-1). e.g. in H2SO4 (H, +1). 7. Oxygen in compounds is assigned an oxidation state of -2. Exception - Peroxide, e.g. H2O2 (O = -1). e.g. in H3PO4 (O, -2). 8. The sum of the oxidation states of all the atoms in a species must be equal to net charge on the species. e.g. Net Charge of HClO4 = 0, i.e. [+1(H)+7(Cl)-2*4(O)] = 0 Net Charge of CrO42-=-2, To solve Cr's oxidation state: x - 4*2(O) = -2, x = +6, so the oxidation state of Cr is +6.
