Final answer:
An abbreviated qualitative analysis scheme distinguishes the presence of specific ions using observable chemical reactions, while quantitative analysis measures exact amounts using techniques like titrations and gravimetric analysis.
Step-by-step explanation:
The abbreviated qualitative analysis scheme in a laboratory setting refers to a streamlined process for determining the presence of specific ions or compounds in a sample without quantifying their amounts. This technique involves a series of chemical reactions that produce observable changes, such as color shifts or precipitate formation, which can be used to infer the presence of particular species. An example of this is reacting a sample with dilute nitric acid and observing a blue solution and a brown gas, which could indicate the presence of copper ions.
In contrast, quantitative chemical analysis involves determining the precise amount of a substance in a sample. Methods such as titrations and gravimetric analysis are used in this context. Titrations measure the volume of a solution needed to react completely with the analyte, and gravimetric analysis involves the separation of the analyte from a sample, followed by mass measurements. Both techniques rely on stoichiometric calculations to quantify the amount of the target substance.