Experience Chemistry Lesson 4.3 & 4.4: Comparing Compounds

​Lesson 4.3 & 4.4: Comparing Compounds

Multiple Choice

Change of a gas directly into a solid

• Sublimation

• Condensation

• Evaporation

• Deposition

Multiple Choice

A gas...

• has a definite shape but no definite volume

• has a definite volume but no definite shape

• has fast-moving molecules

Multiple Choice

Which of the following terms identifies the change from a liquid to solid?

• Melting

• Condensation

• Vaporization

• Freezing

​Representative Units

• The Representative unit is the most basic form of a compound

  • A molecule is the representative unit of a covalent compound

  • An ionic compound is defined by a formula unit

    • Most basic ratio of ions in the compound

Experience Chemistry | Lesson 4.3

​Determining Compound Type

• Ionic compounds are made up of metals and non-metals

• Molecular compounds are made up of only non-metals

  • You can identify Molecular compounds based on the ​the elements

Experience Chemistry | Lesson 4.3

Multiple Choice

Is CaO an Ionic or Molecular Compound

• Ionic

• Compound

Multiple Choice

Is CH₄ an Ionic or Molecular Compound

• Ionic

• Compound

Multiple Choice

Is MgSO₄ an Ionic or Molecular Compound

• Ionic

• Compound

​Covalent Network Solids

• Made up of networks of atoms or molecules held together by covalent bonds

  • Form complex 3-dimensional structures​

• Allotropes: different physical forms of the same element

  • Can have different properties b​ased on the number and arrangement of the atom

Experience Chemistry | Lesson 4.3

​Polymers

• Long repeating chains of molecules

  • Divided into smaller units called monomers​

  • Can be natural or synthetic

Experience Chemistry | Lesson 4.3

​Comparing Metal and Nonmetal

• Metals have too few electrons to form covalent bonds

  • What electrons they have don't stay close to the nucleus when they form ionic bonds​

Experience Chemistry | Lesson 4.3

​Crystalline Structures & Properties of Metals

• Pure metals are crystalline solids

  • Atoms are arranged in one of three repeating patterns​

    • Body-Centered Cubic (BCC)

    • Face-Centered Cubic (FCC)

    • Hexagonal Close-Packed (HCP)

  • The Pattern that atoms are arranged in determines the properties of metals

    • The closer electrons are, the easier it is for metals to be shaped

Experience Chemistry | Lesson 4.3

​Defects & Properties of Metals

• Crystal Dislocations

  • All crystals have some defects in their lattice structure

    • missing electrons, extra atoms, etc.

  • Point Defects: a defect or irregularity within a crystal that occurs at a point in the lattice

    • Three types

      • Interstitial: An extra atom is in a spot it doesn't belong

      • Substitution: A atom is in the wrong spot

      • Vacancy: An Atom is missing

    • Can change properties of the metal

      • Sapphires can change colors based on substitutions

Experience Chemistry | Lesson 4.3

​Dislocations

• Dislocations: Defects caused by entire planes of atoms being inserted or removed

  • Changes the properties of metals

    • More dislocations lower the malleability

  • Can be put into metals on purpose through Work Hardening

    • Bending or shaping a metal repeatedly, increasing the number of dislocations

    • Makes metals stronger, but more brittle

​Alloys

• Many metals are not pure metals

• Alloys: Mixtures of two or more elements, at least one of them a metal

  • Have Superior Properties

    • Steel has Carbon introduced to iron atoms

      • Carbon stops the iron from moving, making the alloy stronger than pure iron

Experience Chemistry | Lesson 4.3

Match

Match the point defect to its description

• Interstital

• Substitution

• Vacancy

An Extra atom is in a spot it doesn't belong

An atom is in the wrong spot

An atom is missing

• An Extra atom is in a spot it doesn't belong

• An atom is in the wrong spot

• An atom is missing