Unit Test CheckUp

1
Unit Test Check-Up

• Second Marking Period
• Introduction to Chemistry

2
Using the Review

• Write your answers on a sheet of paper.
• If you cannot answer a question, look it up in
  your textbook or notes.
• After you have done your best to find to find all
  the answers, check yourself in the Clues section.

3
Density

• If an object has a mass of 50 g and a volume of 2
  cm3, what is its density?

4
Properties of Matter

• A student created the following table to
  describe her observations of a substance. Which
  characteristics can be used to identify the
  substance?

5
Name That Phase

• Nuclei stripped of their electrons, associated
  with nuclear fusion of hydrogen in stars
• High kinetic energy, compressible, molecules are
  spread out, associated with vaporization,
  sublimation
• Takes the shape of its container, associated with
  condensation, melting
• Has a definite shape, associated with freezing

6
Properties of Metals

• Identify which properties are physical and which
  are chemical.
• Malleability
• Ductility
• Conductivity of electricity and heat
• Reactivity with acids
• Reactivity with halogens

7
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• How many protons does an atom of this element
  have?
• How many electrons does a neutral atom of this
  element have?
• How many neutrons does this atom have?

8
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• To what group does this element belong?
• How many valence electrons does this element
  have?
• What does it have in common with members of its
  group?

9
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• Is it a metal, nonmetal, or metalloid?
• Which side of the zig-zag line does it fall on?
• With which metal family does this group bond 11?

10
Chemical Reactions

• Which of the following is a chemical reaction?
• Release of hydrogen gas when metals react with
  acids
• Water becomes a solid at 0O C
• Release of a gas when a soda bottle is opened
• Change in color when an acid reacts with a base

11
Chemical Reactions

• Which of the following forms a covalent bond?
• Metal with a nonmetal
• Metal with a metal
• Nonmetal with a nonmetal

12
Chemical Reactions

• The mass of the products equals the mass of the
  reactants. Why?
• Electrons are shared unequally in a water
  molecule making it polar. Why?
• An atom of an element has a neutral charge. Why?

13
Chemical Reactions

• What is the difference between a coefficent and a
  subscript?
• What is the difference between a solution and
  suspension?
• What is the difference between an endothermic
  reaction and an exothermic reaction?

14
Clues to the Answers
15
Density

• Density mass/volume
• Divide 50 g by 2 cm3 to find the density.

16
Properties of Matter

• Properties of matter that can be used to identify
  a pure substance are phase change temperatures,
  mass/volume at a specified temperature, specific
  gravity, and color.
• Volume is a characteristic that can change
  depending on how much of the substance you have.
• The phase of a substance depends on temperature
  and pressure.

17
Name That Phase

• The phases are organized in order of highest
  kinetic energy to lowest.
• Hint The first is plasma. If water were the
  substance, the rest would be water vapor, rain,
  and ice cube. Think about the names of those
  phases.

18
Properties of Metals

• Physical properties are those that can undergo a
  change without changing the chemistry of the
  metal.
• Reactivity is a chemical property.

19
Properties of Metals

• The following are physical properties of metals
• malleability
• ductility
• conductivity of heat and electricity

20
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• The number of protons equals the atomic number.
• The number of electrons equals the number of
  protons.
• The atomic mass less the atomic number is the
  number of neutrons.

21
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• Look on the Periodic Table to find the group
  number.
• This group is sometimes given the number VIIA for
  the number of valence electrons.
• All members of the group have the same number of
  valence electrons.

22
Periodic Table of the Elements

• 17
• Cl
• Chlorine
• Atomic Mass
• 35

• Chlorine is a gas.
• Metals are to the left, nonmetals are to the
  right, metalloids are along the zig-zag
• Atoms bond to obtain a valence of 8 electrons.
  VIIA would bond with IA 11.

23
Chemical Reactions

• A chemical reaction occurs when a new substance
  is formed.
• Hydrogen is separated from the acid when a metal
  reacts with an acid
• Water and a salt form when an acid reacts with a
  base

24
Chemical Reactions

• Which of the following forms a covalent bond?
• Metal with a nonmetal forms an ionic bond with a
  transfer of electrons from the metal to the
  nonmetal
• Metal with a metal forms a metallic bond with a
  sea of electrons around atoms
• Nonmetal with a nonmetal forms a covalent bond
  with electrons shared either equally or unequally

25
Chemical Reactions

• The mass of the products equals the mass of the
  reactants, because matter is neither created nor
  destroyed during a chemical reaction.
• Electrons are shared unequally in a water
  molecule making it polar, because the oxygen atom
  has a greater pull on the electrons than the
  hydrogen atoms have.
• An atom of an element has a neutral charge,
  because there is one electron for each proton.

26
Chemical Reactions

• A coefficient tells the number of molecules of a
  substance that in a reaction. A subscript tells
  the number of atoms of can element that are in a
  molecule of a substance.
• A solution is so well mixed that it appears to be
  one substance. A suspension is a mixture the
  appears to be more than one substance.
• Endothermic reactions remove heat energy from the
  environment resulting in drop in temperature.
  Thefinal energy of the reaction is higher, but
  the surrounding temperature is lower. Exothermic
  reactions are the opposite. Forming bonds
  requires energy. Breaking bonds releases energy.