Mixtures

MIXTURES

When you add sugar to coffee, tea, iced tea, or lemonade, the sugar disappears. What do you think happens to the sugar?

Pizza Is A Mixture!

Grab a piece of paper and write out your favorite pizza recipe. Don’t forget the ingredients for the crust!

Pizza Is A Mixture!

What happens if you don’t like one of the ingredients that is on a pizza, or in a salad, or in a party mix?

Mixtures can be physically separated!

Mixtures

• A mixture is a combination of two or more substances that are not chemically combined

• Substances in mixtures retain their identity which makes the change a ____?_______change.

Common techniques for Separating Mixtures

Common techniques for Separating Mixtures

Common techniques for Separating Mixtures

Try This!

• With your table partner, think of a way you might separate a mixture of sand, sawdust, and gravel.

• Be prepared to present your suggestions to the class!

Unlike Compounds…

Mixtures do not have a definite mass ratio. Air is an excellent example! Some days there is more water vapor than others. These are our more humid days!

3 Types of Mixtures

• Solutions

• Suspensions

• Colloids

Anticipation Guide

Which of these are solutions?

Air Soft Drinks antifreeze

Ocean water brass

All are solutions! Let’s find out why!

Let’s Talk Solutions

A solution is a mixture that appears to be a single substance

• Contains particles from 2 or more substances

• Described as homogeneous solutions because they have the same appearance and properties throughout the mixture

How are solutions made?

• They dissolve!

Dissolving is when the particles in a solution separate and spread evenly throughout the mixture

What Are the Components Of A Solution?

• The solute is the substance or matter being dissolved or is soluble (able to be dissolved) in the solvent.

• The solvent is the substance into which the solute is dissolved

Let’s think of some examples of a solution

• Turn to your partner and think of one example each of a solution.

• Be prepared to share!

BRAIN FOOD!

Many substances are soluble in water, including salt, sugar, alcohol, and oxygen. Water does not dissolve everything, but it dissolves so many different solutes that it is often called the universal solvent.

Think About It!

• In salt water solution, which is the solute and which is the solvent?

The salt is the solute and the water is the solvent.

So What Happens When The Solution is Two Liquids Or Two

Gases?

• The substance with the greater volume is the solvent!

Can Solids Be A Solution?

YES!

Some examples are alloys which are metals or nonmetals dissolved in metals.

Brass is an alloy of the metal zinc dissolved in copper

Steel, including the steel used to build the Titanic, is an alloy of the nonmetal carbon and other elements dissolved in iron.

Self-CheckYellow Gold is an alloy made from equal

parts copper and silver combined with a greater amount of gold.

Identify each component of yellow gold as a solute or solvent

Copper and silver are solutes and gold is the solvent

Examples of Different States in Solutions

What About Matter That Doesn’t Dissolve In A Solvent?

• This matter is insoluble ( in = not) and forms a mixture that is not homogeneous and is not a solution.

Some Particles In Solutions Are So Small…

How small are they?

So small that they don’t scatter light!

Concentrate on Concentration

Concentration: measure of the amount of solute dissolved in a solvent

Concentration is expressed in grams of solute per milliliter of solvent

Concentrations may be described as either concentrated or dilute

How Do I Determine Concentration of Colorless

Solutions?Let’s Calculate Concentration!

Divide the grams of solute by the milliliters of solvent. For example 35g of salt dissolved in 175mL of water is 35g/175mL= 0.2g/mL

Your Turn!• Sol A has 55g sugar dissolved in

500mL of water

• Sol B has 36g sugar dissolved in 144mL of water

• Which solution is more dilute? Concentrated?

A: 55g/500mL=0.11g/mL B: 36g/144mL=0.25g/mL A is more dilute, B, more concentrated

Let’s Do It Again!

• 46g of Sodium Chloride (NaCl) dissolved in 150mL of water and you need 250mL more of the same solution. How much NaCl do you need to make the additional solution?

• What is the concentration of the solution?

75g additional NaCl Concentration is 0.3g/mL

How Much Can I Dissolve?

If you add too much sugar to your lemonade, all the sugar will not dissolve…Why?

You need to know the solubility of the sugar. The solubility is the amount of solute needed to make a saturated solution using a given amount of solvent at a certain temperature.

Solubility is expressed in grams of solute per 100 mL of solvent

Check It Out!

As the temp is increased, many solids dissolve easier however….

The inverse is true about most gases because the solubility of gases is lower at higher temps!

Suspensions• A suspension is a mixture in which

particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out

• The particles in a suspension are insoluble

• Particles are often described as heterogeneous mixtures because components are easily seen

The Particles In A Suspension Are So Big…

How big are they?

They are so big that they scatter or block light making most suspensions difficult to see through.

They are too heavy to remain mixed without being stirred or shaken

So, What The Heck Is Jello?

• Jello is a colloid!

• A colloid is a mixture in which the particles are dispersed throughout but are not heavy enough to settle out.

• The particles are small and fairly well-mixed

• Solids, liquids and gases can be used to make colloids

Are There Other Examples?

Of Course!

Milk, Mayo, Stick deodorant, and whipped cream

How Small Are The Particles?

• Still big enough to scatter light

• And so small that they cannot be separated by filtration…they are small enough to pass through a filter.

Quick Check

• What are two methods of making a solute move faster?

Mixing, Heating, or crushing the solute

Quick Check• Identify the solvent and solute in a solution

made from 15mL of oxygen and 5mL of helium/

Helium is the solute, oxygen is the solvent

Quick Check

• What are the 3 differences between solutions and suspensions?

Unlike particles in a solutions, particles in a suspension are large enough to settle out, block light, and be trapped by a

filter. Particles in a solution do none of these.