An ion of calcium has a charge of 2+. The ion contains 18 electrons. How many protons does a neutral atom of calcium possess? 18

20

36

2
2

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.

Draw a line graph showing the relationship between temperature in kelvin as a function of kinetic energy.

The activation energy for the reaction no2(g)+co2(g)⟶no(g)+co(g) is ea = 300 kj/mol and the change in enthalpy for the reaction is δh = -100 kj/mol . what is the activation energy for the reverse reaction?