# Solubility Lab #2 Questions

1. Do you think that the air in your classroom is a homogeneous or a heterogeneous
mixture? Explain your answer. Think: Can you breathe in all parts of the room?
Does the air smell the same in all parts of the room? Is the air temperature the same
in all parts of the room? Can you light a candle in all parts of the room?

I think the air in the classroom is heterogeneous because when a person breathes, they breath the air out of your lungs, which might mix in your DNA or any other unique cells of yourself. That means the air is mixed with different kind of air, and the fact that anyone can release any kind of other gas into the air so it smells or looks different. The air from outside would also make it heterogeneous for the air outside includes many other scents.

2. Scientists call water the universal solvent. Are all substances soluble in water?

No. As done in the Solubility #2 lab, barium Sulfate, iron oxide, iron nitrate, potassium sulfate is not dissolvable in water, no matter how long you stir.

3. Use the vocabulary from this inquiry to complete the following statements.

Your father stirs a teaspoon of sugar into his coffee every morning. In this example,
the water in the coffee is the __________ and the sugar is the __________ .
The sugar is soluble/insoluble (choose one) in the water. The coffee is an example of
homogeneous/heterogeneous (choose one) mixture.

Explain why you think coffee is the type of mixture you chose.

Your father stirs a teaspoon of sugar into his coffee every morning. In this example, the water in the coffee is the solvent and the sugar is the solute. The sugar is soluble in the water. The coffee is an example of homogeneous mixture. Coffee is a homogeneous mixture because you can dissolve the sugar into the coffee so that you don’t see the little specks of sugar when you dissolve it in, but that you can still taste the sugar. Plus, sugar is a really soluble substance (You can stir in hundreds of teaspoon of sugar, but still the solution would not saturate).