Chemical reaction between potassium bromide and silver nitrate
Description
In this experiment students add aqueous solutions of potassium bromide and silver nitrate,
previously prepared, and identify the occurrence of a chemical reaction.
Safety
See hazards in Table 1.
Greenness assessment
For the assessment Green Star (GS) was used, results in Fig. 1.
3
P12
P1
2
P5
1
0
P10
P6
P7
GSAI = 41.67
Figure 1. Greenness assessment (GS)
Construction of GS
In Table 1 are presented the hazard codes and the classification of hazards and in Table 2 the
components and punctuations to construct the GS.
Table 1. Hazards of materials usedα
Score: hazards to...
Reagents
Hazard codes
H
E
P
H315;H319;H335
2
1
1
H272 (categoria 2); H314; H410
3
3
3
-
1
1
1
H272 (categoria 3)
1
1
2
Silver bromide
-
1
1
1
Water
-
1
1
1
Reagents
Potassium bromide
Silver nitrate
Water
Waste
Potassium nitrate
α
H – Health; E – Environment; P –Physical; - not present.
Table 2. Scores (S) used to construct the Green Star
Green Chemistry Principle
S
Explanation
P1
Prevention
2
Potassium nitrate H272 (categoria 3)
P5
Safer solvents and auxiliary substances
3
No solvents or auxiliary substances
P6
Increase energy efficiency
3
Room temperature and pressure
P7
Use renewable feedstocks
1
None of the
excluded)
P10
Design for degradation
1
At least one substance is not degradable or break down to
innocuous products
P12
Safer chemistry for accident prevention
1
Silver nitrate H272 (categoria 2); H314
materials/feedstocks are renewable (water
References
Castro, A. F.; Correia, E.; Januário, D. N. Explora 7 - Ciências Físico-Químicas, Porto Editora, Porto, 2012.