Water boils at _ degrees Celsius.
A. 100 B. 32 C. 0 D. 212 Please select the best answer from the choices provided. A B C D
The Correct Answer and Explanation is :
The correct answer is A. 100.
Water boils at 100 degrees Celsius at standard atmospheric pressure, which is defined as 1 atmosphere (atm) or 101.3 kilopascals (kPa) at sea level. This boiling point is a result of the balance between the atmospheric pressure exerted on the water and the vapor pressure of the water molecules. When water is heated, the kinetic energy of its molecules increases. Eventually, the molecules gain enough energy to overcome the intermolecular forces that keep them in liquid form, allowing them to transition into a gaseous state, or steam. At the boiling point, the vapor pressure of the water matches the surrounding atmospheric pressure, causing bubbles of vapor to form within the liquid, leading to a rolling boil.
The other answer choices (B, C, and D) represent temperatures associated with different physical properties of water but not its boiling point at standard pressure:
- B. 32 degrees Celsius is a relatively warm room temperature but is not a notable phase transition point for water.
- C. 0 degrees Celsius is the freezing point of water at standard atmospheric pressure. At this temperature, water transitions from a liquid to a solid, forming ice.
- D. 212 degrees Fahrenheit is the boiling point of water on the Fahrenheit scale, equivalent to 100 degrees Celsius.
It’s also important to note that the boiling point of water can change with altitude and atmospheric pressure. For example, at higher elevations, where atmospheric pressure is lower, water boils at a temperature below 100 degrees Celsius. This is because the vapor pressure required to initiate boiling is reached more quickly in these conditions.