Batting averages

Two very important numbers, the atomic number and the mass number, tell you much of what you need to know about an atom. Chemists tend to memorize these numbers like baseball fans memorize batting averages, but clever chemistry students like you need not resort to memorization. You have the ever-important periodic table of the elements at your disposal. We discuss the logical structure and organization of the periodic table in detail in Chapter 4, so for now, we simply explain what the atomic and mass numbers mean without going into great detail about their consequences. 

A baseball player s batting average is calculated as hits/attempts. For example, a player with 6 hits for 21 times at bat has a batting average of 6/21 = 0.286. This represents a success rate of 28.6%. 

This means that 84.8 percent of the possible yield of ammonia was obtained from the reaction. Calculating percentage yield is similar to calculating a baseball player s batting average, as shown in Figure 12.9. 

Just as batting averages measure a hitter s efficiency, percent yield measures a reaction s efficiency. 

Choose your favorite sport and determine how math plays a part in the record keeping and statistics of that event. For example, what does it mean to have a softball batting average of. 324 ... 

In mathematics, many difTerent types of numbers can be used. Different situations and settings require different types of numbers. When the number of items in a store display is being counted, the numbers 0,1,2,3, and so on are used. However, to present the batting averages of major league ballplayers, we need fractions and their decimal equivalents. For example, if a player has 136 hits in 418 at bats, his average is =. 325. 

Effluent reduction using best available technology economically achievable (BAT) 1-day maximum 30-day average 0.10 kg/kkg 0.021 kg/kkg ... 

NATIONAL (cent.) BAT and NSPS effluent limitations for priority pollutants for direct discharge point sources that do not use end-of-pipe biological treatment Daily maximum Monthly average 380 g/L 142 g/L 40 CFR 455.50, Table 5 EPA1993... 

AADI = Acceptable Average Daily Intake ACGIH = American Conference of Governmental Industrial Hygienists AIC = Acceptable Intake Chronic AIS = Acceptable Intake Subchronic BAT = Best Available Technology CERCLA = Comprehensive Environmental Response, Compensation, and Liability Act DWEL = Drinking Water Equivalent Level EP = Extraction Procedure EPA = Environmental Protection Agency ... 

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