Calculate Energy Required to Turn Ice Into Steam

Calculate Energy Required to Turn Ice Into Steam This worked example problem demonstrates how to calculate the energy required to raise the temperature of a sample that includes changes in phase. This problem finds the energy required to turn cold ice into hot steam. Ice to Steam Energy Problem What is the heat in Joules required to convert 25 grams of -10  °C ice into 150  °C steam?Useful information:heat of fusion of water 334 J/gheat of vaporization of water 2257 J/gspecific heat of ice 2.09 J/g ·Ã‚ °Cspecific heat of water 4.18 J/g ·Ã‚ °Cspecific heat of steam 2.09 J/g ·Ã‚ °CSolution:The total energy required is the sum of the energy to heat the -10  °C ice to 0  °C ice, melting the 0  °C ice into 0  °C water, heating the water to 100  °C, converting 100  °C water to 100  °C steam and heating the steam to 150  °C. To get the final value, first calculate the individual energy values and then add them up.Step 1: Heat required to raise the temperature of ice from -10  °C to 0  °C Use the formulaq mcΔTwhereq heat energym massc specific heatΔT change in temperatureq (25 g)x(2.09 J/g ·Ã‚ °C)[(0  °C - -10  °C)]q (25 g)x(2.09 J/g ·Ã‚ °C)x(10  °C)q 522.5 JHeat required to raise the temperature of ice from -10  °C to 0  °C 522.5 JStep 2: Heat required to convert 0  °C ice to 0  °C waterUse the formula for heat:q m ·ÃŽâ€Hfwhereq heat energym massΔHf heat of fusionq (25 g)x(334 J/g)q 8350 JHeat required to convert 0  °C ice to 0  °C water 8350 JStep 3: Heat required to raise the temperature of 0  °C water to 100  °C waterq mcΔTq (25 g)x(4.18 J/g ·Ã‚ °C)[(100  °C - 0  °C)]q (25 g)x(4.18 J/g ·Ã‚ °C)x(100  °C)q 10450 JHeat required to raise the temperature of 0  °C water to 100  °C water 10450 JStep 4: Heat required to convert 100  °C water to 100  °C steamq m ·ÃŽâ€Hvwhereq heat energym massΔHv heat of vaporizationq (25 g)x(2257 J/g)q 56425 JHeat required to convert 100  °C water to 100  °C steam 56425Step 5: Heat required to convert 100  °C steam to 150  °C steamq mcΔTq (25 g)x(2.09 J/g ·Ã‚ °C)[(150  °C - 100  °C)]q (25 g)x(2.09 J/g ·Ã‚ °C)x(50  °C)q 2612.5 JHeat required to convert 100  °C steam to 150  °C steam 2612.5Step 6: Find total heat energyHeatTotal HeatStep 1 HeatStep 2 HeatStep 3 HeatStep 4 HeatStep 5HeatTotal 522.5 J 8350 J 10450 J 56425 J 2612.5 JHeatTotal 78360 JAnswer:The heat required to convert 25 grams of -10  °C ice into 150  °C steam is 78360 J or 78.36 kJ.

The History of Scissors

The History of Scissors Leonardo da  Vinci has often been credited with inventing scissors, but they predate his lifetime by many centuries. Nowadays, it’s hard to find a household these days that doesn’t have at least one pair. Ancient Scissors The ancient Egyptians used a version of scissors as long ago as 1500 B.C. They were a single piece of metal, typically bronze, fashioned into two blades that were controlled by a metal strip. The strip kept the blades apart until they were squeezed. Each blade was a scissor. Collectively, the blades were scissors, or so rumor has it. Through trade and adventure, the device eventually spread beyond Egypt to other parts of the world. The Romans adapted the Egyptians  design in 100 A.D., creating pivoted or cross-blade scissors that were more in line with what we have today. The Romans also used bronze, but they sometimes made their scissors from iron as well. Roman scissors had two blades that slid past each other. The pivot was situated between the tip and the handles to create a cutting effect between the two blades when they were applied to various properties.  Both Egyptian and Roman versions of scissors had to be sharpened regularly. Scissors Enter the 18th Century Although the actual inventor of scissors is hard to identify, Robert Hinchliffe, of Sheffield, England, should be rightfully acknowledged as the father of modern scissors. He was the first to use steel to manufacture and mass-produce them in 1761 more than 200 years after da  Vinci’s death. Pinking shears  were first invented and patented in 1893 by Louise Austin of Whatcom of Washington to facilitate pinking and scalloping and as a marked improvement over ordinary pinking irons and tools.† Here are some mentions of scissors in print publications over the years, as well as a bit of folklore. From Emar, Capital of Astata, in the 14th  Century BCE By Jean-Claude Margueron Besides ceramics, occasionally collected in large quantities, the houses produced stone and metallic objects illustrating both day-to-day needs and the activities of city merchants: beer filters,  containers, arrow and javelin heads, scales of armor, needles and  scissors,  long nails,  bronze scrapers, millstones, mortars, many kinds of grindstones, pestles, various tools and stone rings. From  The Story of Scissors  by J. Wiss Sons, 1948 Egyptian bronze shears of the Third Century B.C., a unique object of art.  Showing Greek influence although with decoration characteristic of Nile culture, the shears are illustrative of the high degree of craftsmanship which developed in the period following Alexanders conquest of Egypt.  Decorative male and female figures, which complement each other on each blade, are formed by solid pieces of metal of a different color inlaid in the bronze shears.Sir Flinders Petrie ascribes the development of cross-bladed shears to the First Century. In the Fifth Century, the scribe Isidore of Seville  describes cross-bladed shears or scissors with a center pivot as tools of the barber and tailor. Folklore and Superstition More than one expectant mother has placed a pair of scissors beneath her pillow at night somewhere toward the end of her ninth month of pregnancy. Superstition says that this will â€Å"cut the cord† with her baby and prompt labor. And heres another tall tale: Don’t hand those scissors to your best friend. Place them on any available surface and let your friend pick them up. Otherwise, you risk severing your relationship. Some say that those scissors languishing in your catch-it-all drawer can help keep evil spirits out of your home. Hang them by one handle near your door so they form a version of a cross.