Percent, finding

Example 15.1 A 30-p.m-diameter water droplet is evaporating in a chamber. The chamber temperature is 20°C, and the pressure is 760 mmHg. The chamber relative humidity is 50 percent. Find the droplet evaporation rate in grams of water lost per second. 

Blue Jeans Indigo, the dye used to color blue jeans, is prepared using sodium amide. Sodium amide contains the following mass percents of elements hydrogen, 5.17 percent nitrogen, 35.9 percent and sodium, 58.9 percent. Find an empirical formula for sodium amide. 

Meteorites are generally classified into two categories falls and finds. A meteoritic fall occurs when an observer actually sees a meteorite fall to Earth and is able to track and recover the meteorite. The term meteoritic find is used to describe a meteorite that has been found on Earth s surface, although there is no evidence as to when it fell to Earth. In one summary of meteorites, reported in The Handbook of Iron Meteorites, 55 percent of all discoveries were falls and 45 percent finds. 

Determining Mass Percent from a Chemical Formula Each element contributes a fraction of a compound s mass, and that fraction multiplied by 100 gives the element s mass percent. Finding the mass percent is similar on the molecular and molar scales ... 

If the feed is dominated by the middle product (typically more than 50 percent) and the lightest product is present in small quantities (typically less than 5 percent), then the arrangement shown in Fig. 5.106 can be an attractive option. This time the light product must find its way up the column past the sidestream. Again, unless the light product is a small flow and the middle product a high flow, a... 

To convert percent absorption (% A) to absorbance, find the present absorption to the nearest whole digit in the left-hand column read across to the column located under the tenth of a percent desired, and read the value of absorbance. The value of absorbance corresponding to 26.8% absorption is thus 0.1355. 

Example 3 Air Heating Air is heated by a steam coil from 30 F dry-bulb temperature and 80 percent relative humidity to 75 F dry-bulb temperature. Find the relative humidity, wet-bulb temperature, and dew point of the heated air. Determine the quantity of heat added per pound of dry air. 

Cumulative volume over the range of 1 to 50 percent can also be shown to vary approximately as D. This is equiv ent to finding that the number of droplets of a given size is inversely proportional to the droplet area or the surface energy of the droplet. 

Cupronickels (10 to 30 percent Ni) have become very important as copper alloys. They have the highest corrosion resistance of all copper alloys and find apphcation as heat-exchanger tubing. Resistance to seawater is particularly outstanding. 

The outer crust is composed of rust (hematite), precipitate, and settled particulate. Treatment chemicals may also deposit preferentially atop tubercles in response to associated corrosion. It is common to find several percent of zinc and phosphorus compounds in tubercles that grow in zinc- and phosphate-treated waters. Silicates also can be found in... 

Thus we find that between 1900 and 1919, total energy consumption more than doubled from 7,529 trillion Btus to 18,709 Btus and the percentage of total energy consumed in the United States in the form of oil increased from less than 5 percent to about 12 percent. On the other hand, the trend for coal was downward as its percentage of total energy dropped from over 89 percent to 78 percent. 

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