SolutionsUnit 4

Two or more substances together

Mixture of two solids◦ Spoonful of salt mixed together with a spoonful of

baking soda.

Mixture of two liquids◦ Cup of olive oil and a cub of vinegar

Mixture of a solid and a liquid◦ Sand in an aquarium full of water

Mixture

Mixture of two solids

Salt Baking Soda

Salt and Baking Soda Mixture

Simplest kind of interaction

Pieces of the two substances are randomly interspersed and they come to rest against one another

Two kinds of particles coexist and are completely unaffected by being close with one another

Two substances are still identifiably distinct

Mixture of two solids

Mixture of two liquids

When mixed and shaken, the two liquids are distributed throughout one another in tiny droplets

When mixing stops, the two substances rejoin other droplets of their own kind and reassemble themselves into two individual substances

Two substances are still identifiably distinct

Mixture of two liquids

Mixture of a solid and a liquid

Water still a pure continuous mass, but now infused with sand chunks

When mixing stops, gravity pulls on sand to settle at the bottom

Every surface of the sand is in contact with the water

Substances still coexist independent of one another

Mixture of a solid and a liquid

To incorporate one substance uniformly into another substance at the particle level

Example◦ Sugar and water

Dissolve

Dissolve

Dissolve

A mixture formed when one substance dissolves in another

What dissolves is known as the solute

What the solute dissolves into is the solvent

Solution

Between the sugar and the water, which is the solute and which is the solvent?

Solute?Sugar

Solvent?Water

Question

The Air◦ Solvent Nitrogen gas◦ Solute Oxygen gas

Brass◦ Solvent Copper◦ Solute Zinc

Examples

Copper (Solvent) + Zinc (Solute) = Brass

Brass

The amount of solute dissolved in a measure of solvent

Imagine two beakers with 100 mL of water in each. One has 5g of sugar, the other 10g of sugar

Concentration

Example

5g Sugar 10 g Sugar

How are the two solutions the same?

Answer◦ Both contain water and sugar◦ Both are clear◦ Same amount of Water

Questions

How are the two solutions different?

Answer◦ Amount of solute (sugar)

Questions

1st – Mass Ratio◦ Ten grams of sugar in 90 g of water produces a

10% sugar solution Total mass = 10g + 90g = 100g 10g sugar divided by 100g = 10%

2nd – Parts per thousand or Parts per million◦ Every liter (1000mL) of seawater contains 19 g of

chlorine particles.◦ So there are 19 parts per thousand of chlorine in

seawater

Ways to express concentration

Saturated – a solution with the maximum amount of dissolved solute

A fixed amount of water will dissolve a certain amount of sugar.

If more sugar is added, it will not dissolve, but fall to the bottom of the container.

Saturation