2007-08-21 23:37:16 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
The actual measured temperature at 1.0 atmospheres of pressure is 3.984 °C. To understand why water is the most dense at this temperature, one need to understand the nature of hydrogen bonding and its effects on structure.
Water molecules do not exist as simple free floating molecules except as a gas. Below the boil point the molecules of liquid water always align themselves by inter-molecular hydrogen bonding. below 10 °C or so the hydrogen bonding becomes very important.
There seems to be two possible shapes on multiple molecular interactions. They both contain the same number of molecules, but one contains more volume (usually called the ES or expanded shape) and the other CS (for condensed shape). These can interchange, but as thermal energy is removed from the system (cooling the water down to 3.984 °C) the CS becomes the most abundant. There is also where the density is greatest.
Below this temperature, the CS form begins to rearrange and more of the ES is present. Density lowers.
2007-08-28 16:31:10 · answer #1 · answered by Richard 7 · 9⤊ 0⤋
Water At 4 Degrees Celsius
2017-01-13 08:10:47 · answer #2 · answered by few 4 · 0⤊ 0⤋
At temperature below 4 oC the water molecules will start to bcome even closer. However the hydrogen bond that forms between them during the formation of ice results an open structure( which means more empty space compared with 4 0C) It will priduce ice which less dense than water at 4 0c. Thats why ice floats
2007-08-22 00:44:28 · answer #3 · answered by mythili 2 · 2⤊ 0⤋
At 4 Deg C, the molecules are at their most compact state. Below this temperature, microscopic ice crystals begin to form and the mixture begins to expand.
2007-08-21 23:43:57 · answer #4 · answered by cards736 2 · 1⤊ 0⤋
Water molecules normally are free flowing and energetic but not compared to gas molecules. When water reaches this stage, its atoms tend to become closer to each other and therefore it becomes a solid, ice.
2007-08-28 01:39:25 · answer #5 · answered by yahooligan! 3 · 0⤊ 0⤋
Water is at its maximum density at 4C because at this temperature there is the greatest pulling together of the molecules due to hydrogen bonding and the least thermal motion trying to drive them apart.
2007-08-22 00:13:09 · answer #6 · answered by Gervald F 7 · 0⤊ 0⤋
it is near freezing point.
2007-08-29 16:13:49 · answer #7 · answered by Anonymous · 0⤊ 1⤋