Boiling point?

Question

As a liquid is heated at constant pressure, its temperature increases. This trend continues until the boling point of the liquid is reached. No further rise in temperature of the liquid can be induced by heating.

Please explain.

Answer 1

The boiling point of a substance is defined at the temperature at which the vapor pressure of the liquid is the same as the surrounding atmospheric pressure. In your constant-pressure example, the boiling point is reached when the pressure exerted on the environment by gas molecules in equilibrium with your liquid is the same as the pressure exerted by the atmosphere on your sample.

The boiling of a liquid has two stages. In the first stage, heat added to the liquid raises the liquid's temperature until the boiling point is reached. In the second stage, the liquid must be converted to a gas, and heat added to the liquid is used to accomplish this. In this second stage, the temperature of the liquid remains constant.

At first, this might seem counterintuitive. After all, if you heat something, it gets hotter, right? Not always. When a substance is in the liquid state, its molecules have a certain degree of mobility. They are not held in the rigid crystal structures characteristic of solids, so liquid molecules can move around. This is why a liquid takes the shape of the container that holds it. However, liquid molecules do not possess enough energy to completely separate from one another, as they can in the gaseous state. There are intermolecular forces at work that encourage liquid molecules to remain close together. At a liquid's boiling point, heat added to the liquid is used to disrupt these intermolecular forces, which separates the molecules from one another and gives them enough mobility to enter the gaseous state.

The energy required to heat a liquid to its boiling point from ambient temperature is called sensible heat and causes an increase in temperature. The heat required to convert a liquid to a gas at the boiling point is called latent heat and causes a phase change at constant temperature.

Answer 2

Think of it this way: If the temperature of the liquid was any hotter, it wouldn't be a liquid. It would be a gas.

Your statement is correct. As long as pressure stays constant, a liquid can't exceed its boiling point. If it did exceed its boiling point, it would no longer be a liquid. This is easily confirmed by testing.

Answer 3

Because if you heated it any further it would be a gas. Seriously, that's just about all there is to it. When a liquid is boiling and you add more heat to it, instead of making it hotter, you just make it boil faster.

Answer 4

Water has a greater robust freezing element and a melting element by using very solid charm between water molecules, giving upward push to the formation of hydrogen bonds. even nevertheless it truly is staggering to discover that RMM (relative molecular mass) of comparable different compounds like water, which has H2O=18 in comparison with Methane (RMM=sixteen), Ammonia (RMM=17) are ALL gases at 0 tiers different than water, it is at it truly is sturdy state. the clarification is as above, besides, it has a extreme latent warmth of vaporization, requiring very lots of capability to over some the forces of charm between the molecules, permitting them to alter from sturdy to liquid, and liquid to gas. wish this facilitates!