Ionic salts are used for melting ice on roads for two reasons: they are effective at lowering the freezing point when they dissolve in the water and they sometimes release heat when they dissolve in the water. The heat of solution depends on the energy involved in breaking apart the salt and the energy involved in dissolving the ions in water (hydration). The enthalpy of hydration for each ion depends on the strength of the intermolecular force between the ion and water, which is electrostatic and follows Coulomb's law. Rank the following in order of their predicted ability to melt ice due to their heat of solution:

a. NaCl
b. KCl
c. CaCl2

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change. when the temperature in a room increases from 25°c to 33°c, changes from a solid to a liquid. in a lab, methane and nitrogen are cooled from -170°c to -200°c. the methane freezes and the nitrogen . when gold is heated to 2,856°c it changes from a liquid to a .

If you have 5.25 grams of methane (ch4), how many grams of co2 will you produce ?

Astudent made a graph plotting the progress of a reaction over time. the student forgot to label the y-axis of the graph. a graph is shown with two graph lines. one graph line starts at a higher position on the y axis and slopes downwards towards the right. the other graph line starts at a lower position on the y axis and slopes upwards towards the right. the two graph lines stop short of intersecting each other and continue as separate lines which gradually become straight and parallel to the x axis. a vertical line is shown at a point where the two graph lines finally became parallel to the x axis. this vertical line is labeled equilibrium. the title on the x axis is time and an arrow pointing towards the right is shown above time. the title on the y axis is left blank. what best explains the label that the student should use on the y-axis? amount, because as the amount of product decreases, the amount of reactant increases over time. reaction rate, because forward and backward reaction become equal at equilibrium. amount, because the amounts of reactants and products become constant after equilibrium is reached. reaction rate, as the rate of forward reaction increases and rate of backward reaction decreases over time.