Multiple states of matter - mixture
Same state of matter - pure
Separated physically- mixture
Consistent properties - pure
Can’t be separated- pure
Can’t be a single element - mixture
K2Cr2O7 + 14HCl → 2CrCl3 + 2KCl + 3Cl2 + 7H2O
the correct option is :
K2Cr2O7, because the oxidation number of Cr changes from +6 to +3.
<u>Oxidation number of Cr in K2Cr2O7 is:</u>
K2Cr2O7 = 2K + 2 Cr + 7 O
= 2(+1) + 2Cr + 7(-2)
= 2 + 2Cr -14
[total charge on K2Cr2O7 = 0], Hence;
2 + 2Cr -14 = 0
2Cr -12 = 0
2Cr = 12
Cr = 12/2
<u>Cr = +6</u>
<u>Oxidation number of Cr in CrCl3 is:</u>
CrCl3 = Cr + 3Cl = 0
Cr + 3(-1) = 0
Cr -3 = 0
<u>Cr = +3</u>
Hence Cr is changing its oxidation number from
+6 in K2Cr2O7 to +3 in CrCl3.
Since the oxidation number of Cr [ +6 → +3] is decreasing here,
Cr is getting reduced.
so K2Cr2O7 is an oxidizing agent,as it is getting itself reduced and oxidizes others.
Answer:
. 1. This amino acid has a positively charged R group: ARGININE
2. This amino acid has a negatively charged R group: ASPARTATE
3. This amino acid has a neutral polar R group: NONE
4. This amino acid has a nonpolar aliphatic R: VALINE
5. This amino acid has an aromatic R group: TRYTOPHAN
Explanation:
1) Arginine contains an extra amino group bearing a positive charge, in its chain which imparts basic properties to it
2) Aspartate contains an extra carboxyl group with a dissociable protron. Once the Protron is dissociated, it carries an extra negative charge in its side chain (R)
3) NONE of the amino acids given belong to this group because amino acids with neutral polar R groups contain functional groups that form hydrogen bonds with water. But, this is not the case with tryptophan aspartate valine or arginine
4) Valine has a R group that is hydrocarbon in nature and thus hydrophobic.
5) Trytophan has a benzene ring in its side chain
