Name: e). (3 pts.) which one of these is NOTanintensiveproperty (select one)? (a
ID: 558598 • Letter: N
Question
Name: e). (3 pts.) which one of these is NOTanintensiveproperty (select one)? (a) molarity (b) normality (c) density (d) number of moles (15pts;3pteach) List ALL ions and molecules presentinan aqueous solutionoftH0 (a) HCIO(aq) Ions): H+Co Molecule(s) Molecule(s): H+so, b)HSoag)lon: +s+ e) NaOH(aq) (d) NaNO,(aq) (e) CaCl2(aq) lon(s): H,+Sta Ion(s) Moleculets): Na'+ OtH 32 Molecule(s) lono:CaCMolecalto: Ion(s) .3.6 pts) In the following reaction: S(s) + 2 Na(s)-2 Na2S(s) (a) Sodium (Na) is:/udteed (selectoralized or reduced) (S) is:dized (select oxidized or reduced) 4. (6 pts) What is oxidized and what is reduced in this reaction (indicate an atom in a molecule, Tor cxample Clatom inHC)? " Br207(aq) + H2O2(aq) BrO·-(aq) +01g) reduced: oxidized om h .5. (3 pts) Which one of the following compounds exists in an aqueous solution as a molcule? (a) HBrO2(b) NaBrO (c) HBr (d) KBrO (e) HBrO4 (f) none of them #6 (15 pts; 3 pt each) Give the oxidation number of the underlined element in each of the following (a) Na:02 (b) CIO, (c) Ca(BrO4) (d) CH12 (e) H2SO4Explanation / Answer
1. An intensive property is the one that does not depend on the size of the system, this properties can be said that define a substance, concentration and density are intensive properties
number of moles is not an intensive property, it depends on the mass of the system
2. ions are:
H3O+ and ClO-; HClO4 + H2O -------> H3O+ + ClO4-
2H3O+ and SO4-2; H2SO4 + H2O -------> H3O+ + ClO4-
Na+ and OH-; NaOH + H2O ===== Na+ + OH- + H2O
Na+ and NO3-; NaNO3 + H2O ===== Na+ + NO3- + H2O
Ca+2 and 2Cl-; CaCl2 + H2O ===== Ca+2 + 2 Cl- + H2O
3. The Na2S, remember that it must have a total valence of 0
the Na has a valence of +1, we can see that there are 2 Na so it has +2, the sulphur must have a valence of -2
from the reaction the Na(s), which has a valence of 0 gets a valence of +1
the Sulphur goes from 0 to -2
When a element has an inferior number than the original like the sulphur in this case, it is because it has gained an electron, this is a reduction
When an element has a superior number than the original , like sodium in this case it is because it has lost electrons, this is an oxidation so the answer is
sodium is being oxidized and Sulphur is being reduced