Under which of the following conditions we can boil water at room temperature?
Evaporation occurs at temperatures below the boiling point, and occurs on the liquid's surface. For molecules of a liquid to evaporate, they must be located near the surface, be moving in the proper direction, and have sufficient kinetic energy to overcome inter-molecular forces present in the liquid phase.
The conversion of gas into liquid is called
Condensation is the process in which any substance change into liquid from its gaseous form. Eg- Water changes from its gaseous form by the process of condensation.
The fusion is the process in which
Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.
The ice floats on water because
Ice floats on water because it is less dense than water.
When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions. Because the molecules are not moving, they're not able to form as many hydrogen bonds with other water molecules. This leads to ice water molecules not being as close together as in the case of liquid water, thus reducing its density.
Most substances in their solid form are more dense than their liquid forms. The opposite is true in water. This property of water is somewhat unusual and rare.
Water is actually most dense at 4ºC. At any temperature below or above 4ºC, water becomes less dense.
Which of the following does not affect the rate of evaporation?
Ice is in solid state while water is in liquid state. Thus, ice will convert into liquid state by absorbing the latent heat of fusion. On the other hand, no such heat will be absorbed by water as it is already in the liquid state. Hence, ice will absorb more energy than water at 273K or 0o C. The more is the energy absorbed, the more is the cooling effect. As a result, the cooling effect of ice at 273 K or 0o C is more than water at the same temperature.
Which of the following is not an endothermic process?
Solids and gases mix/dissolve in water
Gases can dissolve in water.
The dissolving of a gas in water depends on the interaction between the molecules of the gas and the water molecules.
The amount of gas that can be dissolved in water depends on the temperature of the water.
More gas can dissolve in cold water than in hot water.
Choose the correct statement from the following:
By heating a gas, the volume of gas will expand because molecule of that gas will get kinetic energy through heating.
As the pressure of air decreases, the boiling point of the liquid
When atmospheric pressure is decrease, the boiling point of water will also decrease because boiling point is the temperature at which the vapour pressure of a liquid becomes equal to that of the atmosphere. If the atmospheric pressure decreases, then the vapour pressure of the liquid will also have to be decreased, for which the liquid has to be cooled down. Hence the boiling point of a liquid decreases.
Which among the following can exist in vapour state?
Water is the only substance here which can exist in vapour state.