Physical Science 3-3: Compounds & Mixtures

​Lesson 3-3: Compounds & Mixtures

Multiple Choice

the central region of an atom where its neutrons and protons are is its 

• nucleus 
• electron cloud
• core 
• center 

Multiple Choice

What is the name of group number 1 on the periodic table?

• halogens

• noble gases

• alkali metals

• alkaline earth metals

Multiple Choice

A row on the Periodic Table of Elements is called a....

• family

• period

• row

• isotope

Multiple Choice

Which element is found in group 2, period 6?

• Oxygen (O)

• Barium (Ba)

• Selenium (Se)

• Carbon (C)

Multiple Choice

Which halogen is found in period 4?

• Krypton (Kr)

• Xenon (Xe)

• Bromine (Br)

• Iodine (I)

Lesson Objectives

• Define compounds

  • Identify when a substance is a compound

• Calculate the atomic mass of a compound

• Define a mixture

• Identify different types of mixtures

​Introduction

• Elements are the most basic form of matter, but most of the universe is more complex than a single atom

• When we look at more complex forms of matter, there are different categories we can divide them into

What are compounds?

• Compound: a pure substance composed of two or more elements joined together by chemical bonds

  • Can be different elements or multiples of the same

• Compounds are written as chemical formulas that represent the elements in them

  • Use subscripts to tell you the amount of each element

properties of compounds

• Compounds have their own physical and chemical properties that can be used to identify them.

• The properties of a compound are influenced by the elements that make it up, but are not identical.

  • Example: Sodium & Chlorine are extremely reactive elements, but sodium chloride is stable and safe to consume

• Compounds are able to be broken down into their individual elements through the addition of energy to a system

  • Generally heat or electricity

Masses of compounds

• Recall: Every element has an atomic mass

  • Found on the periodic table, generally underneath the elemental symbol

• When elements combine to form compounds, all of those masses add together to give the compound its own mass in amu

• In this class, we will round our atomic masses to whole numbers to keep things simple

Calculating the mass of a compound sample problem 1

• Calculate the mass of water, which has the formula H₂O

  • Step 1: Identify the elements in the compound

    • Hydrogen

    • Oxygen

  • Step 2: Identify how many of each element are in the compound

    • There are two Hydrogens, and one Oxygen

  • Step 3: Add the mass of every atom in the compound together

    • Make sure you count both hydrogen!!

Calculating the mass of a compound sample problem 1

• Calculate the mass of water, which has the formula H₂O

  • Step 1: Identify the elements in the compound

    • Hydrogen

    • Oxygen

  • Step 2: Identify how many of each element are in the compound

    • There are two Hydrogens, and one Oxygen

  • Step 3: Add the mass of every atom in the compound together

    • Make sure you count both hydrogen!!

Fill in the Blanks

Calculating the mass of a compound sample problem 2

• Calculate the mass of Sodium Chloride, which has the formula NaCl

  • Step 1: Identify the elements in the compound

    • Sodium

    • Chlorine

  • Step 2: Identify how many of each element are in the compound

    • There is one sodium and one chlorine

  • Step 3: Add the mass of every atom in the compound together

Calculating the mass of a compound sample problem 2

• Calculate the mass of Sodium Chloride, which has the formula NaCl

  • Step 1: Identify the elements in the compound

    • Sodium

    • Chlorine

  • Step 2: Identify how many of each element are in the compound

    • There is one sodium and one chlorine

  • Step 3: Add the mass of every atom in the compound together

Fill in the Blanks

Calculating the mass of a compound sample problem 3

• Calculate the mass of Sucrose, which has the formula C₁₂H₂₂O₁₁

  • Step 1: Identify the elements in the compound

    • Carbon

    • Hydrogen

    • Oxygen

  • Step 2: Identify how many of each element are in the compound

Calculating the mass of a compound sample problem 3

• Calculate the mass of Sucrose, which has the formula C₁₂H₂₂O₁₁

  • Step 1: Identify the elements in the compound

  • Step 2: Identify how many of each element are in the compound

    • 12 Carbon

    • 22 Hydrogen

    • 11 Oxygen

  • Step 3: Add the mass of every atom in the compound together

Calculating the mass of a compound sample problem 3

• Calculate the mass of Sucrose, which has the formula C₁₂H₂₂O₁₁

  • Step 1: Identify the elements in the compound

  • Step 2: Identify how many of each element are in the compound

    • 12 Carbon

    • 22 Hydrogen

    • 11 Oxygen

  • Step 3: Add the mass of every atom in the compound together

Fill in the Blanks

What are Mixtures?

• Mixture: A combination of two or more substances that are not chemically combined

  • There is no chemical change when a mixture is made, and substances maintain their physical and chemical properties

Types of Mixtures

• Overall, we put mixtures into two broad groups depending on how the mixture appears

• Homogeneous Mixture: A mixture in which all components look like a single substance

• Heterogeneous Mixture: A mixture in which different components can be seen and distinguished

Methods of Separating a mixture

• Most means of separating mixtures involve taking advantage of physical properties and Physical changes

  • magnetism, solubility, etc

• Distillation: A process that separates a mixture based on boiling points

• Filtration: Separating a solid from a liquid using a semipermeable barrier

• Centrifuge: A machine that separates a mixture based on the different densities of the components in the mixture

  • Spins the mixture around so that the most dense particles settle on the bottom, with the least dense on the top

• Chromatography: A means of separating a mixture through a medium based on the different speeds the components can move.

Ratios of Mixtures

• With Compounds, the components will always occur in a fixed ratio

  • Sodium Chloride is always made of one sodium atom and one chlorine atom

• Mixtures do not have fixed ratios and can be adjusted to differing amounts

Categorize

Options (10)

Salad

Vegetable Soup

Trail Mix

Granola with Nuts

Salt Water

Sugar Water

Coffee

Tea

Chili

Air

Organize these mixtures by which type they are

Heterogeneous Mixture

Homogeneous Mixture

Multiple Choice

Making a mixture results in ___________________ only.

• chemical reactions
• separate parts
• physical changes
• two subtances

Solutions

• Solutions are a special type of homogeneous mixture where the particles of the substances are evenly spread out

  • The appearance and properties are the same throughout the mixture

• Solutions are made through the process of dissolving, and are made of two components

  • Solvent: The substance that is present in the largest amount

  • Solute: The substance present in smaller amounts

Types of Solutions

• Water is a common solvent because so many substances dissolve in

  • Also called "The Universal Solvent"

• Many liquids can act as solvents, and some solutes only dissolve in certain solvents

• Gases and solids can also act as solvents by dissolving other substances

  • Alloy: Solid solutions in which a metal is a solvent

Solution Concentration

• Concentration: The amount of solute in a given amount of solvent

• Concentration can be described in two different manners

  • Dilute: A small amount of solute is dissolved

  • Concentrated: A large amount of solute is dissolved

• Concentration can be calculated by dividing the mass of solute by the volume of solvent

  • Generally shown as g/ml

Calculating Concentration Sample Problem 1

• What is the concentration in g/ml of a solution that has 35 g of salt dissolved in 175 ml of Water?

  • Step 1: Identify the variables

    • Mass= 35 grams

    • Volume= 175 ml

  • Step 2: Plug into your equation and solve

Calculating Concentration Sample Problem 2

• What is the concentration in g/ml of a solution that has 90 g of salt (NaCl) dissolved in 3500 ml of Water?

  • Step 1: Identify the variables

    • Mass=

    • Volume=

  • Step 2: Plug into your equation and solve

Calculating Concentration Sample Problem 2

• What is the concentration in g/ml of a solution that has 90 g of salt (NaCl) dissolved in 3500 ml of Water?

  • Step 1: Identify the variables

    • Mass= 90 grams

    • Volume= 3500 ml

  • Step 2: Plug into your equation and solve

Calculating Concentration Sample Problem 3

• What is the concentration in g/ml of a solution that has 70 g of sucrose (C₁₂H₂₂O₁₁) dissolved in 1000 ml of Water?

  • Step 1: Identify the variables

    • Mass=

    • Volume=

  • Step 2: Plug into your equation and solve

Calculating Concentration Sample Problem 3

• What is the concentration in g/ml of a solution that has 70 g of sucrose (C₁₂H₂₂O₁₁) dissolved in 1000 ml of Water?

  • Step 1: Identify the variables

    • Mass= 70

    • Volume=1000

  • Step 2: Plug into your equation and solve

Solubility

• There is a limit to how much solute you can add to a solution

• Solubility: How much solute dissolves in an amount of solvent at a certain temperature

  • For most solids, increasing the temperature increases the amount of solute that can dissolve

    • If the solution becomes cooler, some of the dissolved particles settle out of the solution

Dissolving Gases in Liquids

• Gases can also be dissolved in liquids

• Gases become less soluble at higher temperatures

  • Causes a can of Pop to go flat if you leave it out in warmer temperatures

  • It can affect the amount of Oxygen in water

Dissolving Solids in Liquids

• Solids can be dissolved at different rates based on three different factors

  • Mixing: Moving the particles causes them to spread out more quickly

  • Heating: Increasing the temperature causes particles to move faster and spread out more

  • Crushing: Making particles smaller allows them to mix with the solvent faster

Suspensions

• Suspensions: Mixtures where the particles of material are large enough to settle out

• Particles in a suspension are large enough to scatter or block light

• Can be separated with a filter

Colloids

• Colloid: A mixture in which particles are spread throughout, but are not large enough to settle out.

  • Particle size is between a suspension and a solution

    • Can not be separated with a filter

  • Particles are large enough to scatter light

The Tyndall Effect

• It can sometimes be hard to tell the difference between a solution, suspension, and colloid

• One way to tell is to observe how light passes through the mixture

• The Tyndall Effect occurs when light is scattered by the particles in a colloid

Multiple Choice

What is a solvent

• the liquid in which a solute is dissolved to form a solution.
• Another word for solution
• A thing that make drinks turn colors
• Its a metal molecule

Multiple Choice

Based on the graph, How many grams are soluble in 100 g of water at 100 ºC?

• 300 grams

• 250 grams

• 100 grams

• 50 grams

Multiple Choice

The substance being dissolved in a solution is the....?

• solution

• solute

• solvent

• mixture

Multiple Choice

A substance that is made up of two or more different types of atoms bonded together e.g. water is called a....

• compound
• solvent
• element
• solution