What kind of reaction is indicated by two arrows pointing in opposite directions?

Which statement describes how phase changes can be diagrammed as a substance is heated? the phase is on the y-axis and the temperature is on the x-axis. the temperature is on the y-axis and the phase is on the x-axis. the time is on the y-axis and the temperature is on the x-axis. the temperature is on the y-axis and the time is on the x-axis.

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

Calculate the number of moles of ethane in 100 grams