Question

pre - investigation questions
before watching the demonstration, predict what you think will happen:

1. if you stir sugar in water versus leaving it alone, which do you think will dissolve faster? why?
2. would crushed ice or a whole ice cube melt faster in warm water? explain your reasoning.
3. do you think sugar dissolves better in hot coffee or iced coffee? whats your hypothesis?
4. between salt and sugar, which do you predict dissolves faster in water? what makes you think this?

Explanation:

1. Stirring sugar in water increases the contact between sugar and water molecules, speeding up dissolution.
2. Crushed ice has a larger surface - area to volume ratio, allowing more contact with warm water and melting faster.
3. Higher temperature increases the kinetic energy of molecules, so sugar should dissolve better in hot coffee.
4. Salt generally dissociates into ions and may dissolve faster due to its ionic nature and the way it interacts with water compared to sugar's molecular structure.

Answer:

1. Stirring sugar in water will dissolve faster because it increases the rate of contact between sugar and water molecules.
2. Crushed ice will melt faster in warm water as it has a larger surface - area to volume ratio.
3. Sugar will dissolve better in hot coffee as higher temperature enhances the dissolution process.
4. Salt may dissolve faster in water due to its ionic nature and different interaction with water molecules compared to sugar.