Boiling Point Elevation Flashcards
What defines the boiling point of a liquid?
The boiling point occurs at the temperature where the vapor pressure of the liquid equals the vapor pressure above it.
At what temperature does water boil at atmospheric pressure?
Water boils at 100 °C at atmospheric pressure (1 atm).
How does reducing pressure affect the boiling point of water?
When pressure is reduced (under vacuum), water boils at temperatures lower than 100 °C.
What happens to the boiling point when pressure is applied to water?
When pressure is applied, water boils at temperatures higher than 100 °C.
How does adding a solute, like salt or sugar, affect the boiling point of water?
Adding solute raises the boiling point because it reduces the vapor pressure of the solution compared to pure water.
What is boiling point elevation?
Boiling point elevation is the phenomenon where the boiling point of a solvent increases when a solute is dissolved in it.
Explain the concept of “thread” stage in candy making.
The “thread” stage occurs at around 110 °C with a sugar concentration of ~85%, where the syrup forms a viscous fluid that does not ball up.
What defines the “soft-ball” stage in sugar solutions?
The “soft-ball” stage occurs between 113-115 °C, where the sugar concentration reaches ~85%, forming a ball that flattens when removed from cold water.
Describe the “hard-ball” stage in candy making.
The “hard-ball” stage occurs between 121-129 °C with a sugar concentration of 92%, forming a firm ball that retains its shape but is still malleable.
What occurs at temperatures >160 °C during candy making?
At temperatures >160 °C, sugar begins to caramelize, forming polymers of sugar monomers instead of further increasing in concentration.
