Track quiz
Here are the nine rules, in the exact words each lab uses.
| Idea | The rule, as the lab applies it |
|---|---|
| Three words | A solution is a uniform mixture. When a solid dissolves in a liquid, the solid is the solute. The liquid is the solvent. With two liquids, the smaller amount is the solute. |
| What water can dissolve | Water dissolves many things, such as sugar and salt. It does not dissolve everything, such as sand or oil. A substance may dissolve in one solvent but not in another. |
| How much will go in | At one temperature, a solvent has a limit. A fixed amount dissolves only so much solute. This maximum is its solubility. Any extra solute stays undissolved. |
| Warmth moves the limit | For most solids, solubility rises as the water gets warmer. For gases it usually falls. So cold water holds more oxygen than warm water. |
| A glass at its limit | A saturated solution holds all the solute it can at that temperature. An unsaturated solution can still dissolve more. Cooling a saturated solution of a solid makes some solute come out. |
| How strong is it | Concentration is the amount of solute in a fixed amount of solution. More solute in the same amount makes it more concentrated. Dilute and concentrated are relative words. |
| Uniform or not | A uniform mixture is the same all through. Its parts cannot be seen apart. This is a solution. In a non-uniform mixture, the parts differ from place to place. |
| Density | Density is mass divided by volume. Water has a density of about 1 g in each cm³. |
| Float or sink | An object floats if its density is less than the liquid's. It sinks if its density is more. |
Salt is dissolved in water. Which is the solvent?
A thick syrup has more sugar than water. Which is the solute?
A little glycerine is mixed into a lot of water. Which is the solute?
Which of these does not dissolve in water?
Grease will not dissolve in water. What can you do?
You add salt spoon by spoon. After six spoons, the seventh stays at the bottom. What does this show?
Does stirring longer let the water dissolve more than its limit?
Baking soda has stopped dissolving in cold water. What happens when you warm the water?
Oxygen dissolves better in hot water than in cold. True or false?
A solution cannot dissolve any more solute at this temperature. What is it?
A saturated sugar solution is cooled. What happens?
Cup A has 6 spoons in 200 mL. Cup B has 4 spoons in 100 mL. Which is more concentrated?
Sand is stirred into water. What kind of mixture is it?
Air is a mixture of gases. Is it a uniform mixture?
A stone has mass 45 g. It lifts the water from 60 mL to 75 mL. What is its density?
Strong salt water is 1.2 g/cm³. A clay ball has density 1.1 g/cm³. What happens in the salt water?
Read NCERT Chapter 9, The Amazing World of Solutes, Solvents, and Solutions. It also shows how to read a measuring cylinder. And it shows how heat changes density.
Next: Light: Mirrors and Lenses.