It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. carry out the following calculation to test this hypothesis. at 1 atm pressure, ice melts at 273.15 k, δhfus=6010j⋅mol−1, the density of ice is 920. kg⋅m−3, and the density of liquid water is 997 kg⋅m−3.
part a: what pressure is required to lower the melting temperature by 4.7 degrees celsius? part b: assume that the width of the skate in contact with the ice has been reduced by sharpening to 0.019 cm, and that the length of the contact area is 18 cm. if a skater of mass 79kg is balanced on one skate, what pressure is exerted at the interface of the skate and the ice? part c: what is the melting point of ice under this pressure?

Nconcentration refers to the molar concentration of an ion in solution. it may be identical to, or greater or less than, the molar concentration of the compound containing the ion that was used to make the solution. for soluble salts, the molarity of a particular ion is equal to the molarity of that compound times the subscript for that ion. for example, 1 m of alcl3 is 1 m in al3+ and 3 m in cl−. 1 m of (nh4)2so4 is 2 m in nh4+ and 1 m in so42−. part a what is the concentration of k+ in 0.15 m of k2s? view available hint(s) nothing m m part b if cacl2 is dissolved in water, what can be said about the concentration of the ca2+ ion? view available hint(s) if is dissolved in water, what can be said about the concentration of the ion? it has the same concentration as the cl− ion. its concentration is half that of the cl− ion. its concentration is twice that of the cl− ion. its concentration is one-third that of the cl− ion. part c a scientist wants to make a solution of tribasic sodium phosphate, na3po4, for a laboratory experiment. how many grams of na3po4 will be needed to produce 550 ml of a solution that has a concentration of na+ ions of 0.700 m ? express your answer numerically in grams. view available hint(s) mass of na3po4 n a 3 p o 4 = nothing g provide feedback

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit