Which things dissolves in Water? (teacher made) - Twinkl - Free Printable

Problem Description:

The task is to classify the given items into two categories: those that dissolve in water and those that do not dissolve in water. The items listed are:

- Salt
- Tea
- Vinegar
- Wine
- Milk
- Dental Liquid (e.g., mouthwash)
- Iodine
- Coffee
- Flour
- Oil
- Plastic
- Honey
- Chalk
- Stones
- Lemon Juice

Solution Approach:

To solve this problem, we need to understand the concept of solubility. A substance dissolves in water if its molecules or ions can interact with water molecules and spread throughout the solution. Substances that do not dissolve remain as separate particles or clumps.

#### Key Points to Consider:
1. Polar vs. Nonpolar Substances:
- Water is a polar solvent (it has a partial positive charge on hydrogen atoms and a partial negative charge on oxygen atoms).
- Polar substances (like salt, sugar, vinegar) generally dissolve in water because they can form hydrogen bonds with water molecules.
- Nonpolar substances (like oil, plastic) do not dissolve in water because they cannot interact effectively with water molecules.

2. Solubility Rules:
- Salts (e.g., salt, iodine) often dissolve in water.
- Acids and bases (e.g., vinegar, lemon juice) usually dissolve in water.
- Organic compounds (e.g., oil, plastic) typically do not dissolve in water unless they are specifically designed to be soluble.
- Solids like chalk and stones are generally insoluble in water.

3. Observational Knowledge:
- Common everyday observations can help determine solubility. For example, salt dissolves in water, while oil floats on top.

Classification of Items:

Let's classify each item based on whether it dissolves in water:

#### Dissolves in Water:
- Salt: Dissolves completely in water.
- Tea: Tea leaves contain compounds (like tannins) that dissolve in water.
- Vinegar: Vinegar is an aqueous solution of acetic acid, so it dissolves in water.
- Wine: Wine contains water and ethanol, both of which are soluble in water.
- Dental Liquid (mouthwash): Typically contains alcohol and other chemicals that dissolve in water.
- Iodine: Iodine crystals dissolve in water, forming a brown solution.
- Coffee: Coffee grounds contain compounds (like caffeine) that dissolve in water.
- Lemon Juice: Lemon juice is an aqueous solution of citric acid, so it dissolves in water.
- Honey: Honey is primarily composed of sugars and water, so it dissolves in water.

#### Does Not Dissolve in Water:
- Milk: Milk is a colloidal suspension of fats and proteins, which do not dissolve in water but remain suspended.
- Flour: Flour is made up of starch particles that do not dissolve in water but can form a paste.
- Oil: Oil is nonpolar and does not mix with water; it floats on top.
- Plastic: Most plastics are nonpolar and do not dissolve in water.
- Chalk: Chalk is primarily calcium carbonate, which is insoluble in water.
- Stones: Stones are solid minerals and do not dissolve in water.

Final Answer:

\[
\boxed{
\text{Dissolves in Water: Salt, Tea, Vinegar, Wine, Dental Liquid, Iodine, Coffee, Lemon Juice, Honey}
}
\]
\[
\boxed{
\text{Does Not Dissolve in Water: Milk, Flour, Oil, Plastic, Chalk, Stones}
}
\]