6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.
In the case of water, that is, when the liquid water gets cooled, it gets contract to a temperature of about 4 degrees is attained. However, after that, it starts to expand somewhat till it moves towards the freezing point, and eventually when it freezes, it expands by about 9 percent.
This characteristic has its source in the composition of the water molecule. In water, there possesses a capacity to produce a network of hydrogen bonds, where each atom of hydrogen is in a line amongst the two atoms of oxygen. This tendency of hydrogen bonding gets robust as the temperature lowers down. The formed ice structure is completely hydrogen-bonded and these bonds permit the structure to get open, thus, expansion takes place.
Water has this unusual
behavior when cooled at 4 degrees Celsius; it expands slightly until
it reaches the freezing point and continue to expand by approximately 9%. This characteristic has something to do with the structure of the water molecule where there is a
strong tendency to form a network of hydrogen bonds and each hydrogen atom is
in a line between two oxygen atoms. These bonds force the crystalline
structure to be very open into hexagonal form and expand dramatically.
When water freezes the molecules become stronger. When the molecules become stronger they expand . The crystalline arrangement is less dense than that of the molecules in liquid form which makes the ice less dense than the liquid water.