CHe 2 mistry Proficiency Review

Pre-review Questions 1.A student ran tests on a mystery substance and found that is has a definite volume, high density, and flows easily. Which state of matter is it and why? a) It is a solid because it has a definite volume and high density. b) It is a liquid because it has a definite volume and high density. c) It is a gas because it has a definite volume and flows easily. d) It is a liquid because it has a definite volume and flows easily.

2.Which of the following correctly describes the motion of particles in a solid? a)They do not move at all. b)They move rapidly around in random patterns. c) They vibrate in a set pattern. d) They flow easily, but slowly around each other.

3. Analyze the table below. The following symbols each represent one atom of different elements: Which of the above correctly represents a chemical equation showing the law of conservation of mass in a chemical reaction? a)I b)II c)III d)IV

4. What happens when wood burns with the oxygen in air to form water and carbon dioxide? a)The mass of the products becomes less than the mass of the reactants. b)Most of the mass of the wood is converted into energy. c)More energy is absorbed than given off in the reaction. d)The mass of the wood and oxygen reacted equals the mass of the products.

5. When photosynthesis occurs, carbon dioxide and water produce glucose and oxygen. The balanced equation is 6 CO H 2 O  C 6 H 12 O O 2. How many molecules of C 6 H 12 O 6 are produced when 18 molecules O 2 are produced? a)1 molecule C 6 H 12 O 6 b)2 molecules C 6 H 12 O 6 c)3 molecules C 6 H 12 O 6 d)6 molecules C 6 H 12 O 6

Kinetic Molecular Theory Explains the forces between molecules and the energy that they possess Matter is composed of small particles (molecules, ions, atoms). The energy and organization of these particles determines the physical state and properties of matter. All particles are in constant, random motion and possess kinetic energy. The amount of kinetic energy is directly related to temperature. Kinetic energy is transferred from one particle to another through collisions.

There are three different, common physical states of matter.

Solids Strong intermolecular attractions hold individual particles close together Particles vibrate Defined volumes and shapes and do not flow High densities

Liquids Particles are randomly packed and close to each other Intermolecular attractions between particles is not as strong as in solids Particles slide over each other but do not completely separate Definite volume but an indefinite shape (take the shape of their containers) Flow.

Gases Intermolecular attractions between particles is very small Particles move far apart from each other Particles are in constant, random motion, independent of each other No specific shape or volume ( take the shape of their containers ) Low densities Flow

SOLIDLIQUIDGAS Particle Arrangement FixedRandom Closeness of Particles Close Far Apart Attraction between Particles StrongModerateLittle to none Motion of Particles Held close by their attractions of charge Slide over each other Move constantly and randomly, independent Volume Definite volume Takes the volume of its container Shape Definite shape Takes the shape of its container Flow Does notEasily Density High High (lower than the correspondin g solid) Low

Activity: Use the information squares in the plastic baggie provided to complete the chart on solids, liquids, and gases. Check your answers with the teacher when you are done.

To Teacher Pass Out Materials Continue presentation with the solution to the table when the majority of students are done.

SOLIDLIQUIDGAS Particle Arrangement FixedRandom Closeness of Particles Close Far Apart Attraction between ParticlesStrongModerateLittle to none Motion of Particles Held close by their attractions of charge Slide over each other Move constantly and randomly, independent Volume Definite volume Takes the volume of its container Shape Definite shape Takes the shape of its container Flow Does notEasily Density High High (lower than the corresponding solid) Low

More Chemistry Review All matter is composed of atoms. Each element is made of a different kind of atom. Atoms of different elements have different masses. Atoms are neither created nor destroyed in chemical reactions. (Law of Conservation of Mass) Atoms of different elements combine in fixed number ratios. Example: H 2 0, H 2 SO 4 More than one ratio possible for a given combination of elements.

Study the Equation C + O 2  CO 2 (Reactants) (Products) Ratio of C to O atoms to form CO 2 is 1 C atom to 2 O atoms (1:2) This equation is balanced. Why??? There is one atom of Carbon and two atoms of Oxygen on both sides of the equation. Atoms have been rearranged in their bonds Number of atoms in reactants equal the atoms in the product

Study the Equation CH 4 + O 2  CO 2 + H 2 O Is this equation balanced? No. The number of atoms of Hydrogen and Oxygen are not the same on each side of the equation. What can you do to make the equation balanced? Add the number 2 before the O 2 and H 2 O molecules CH O 2  CO H 2 O

Study the Equation Subscripts CH O 2  CO H 2 O Coefficients What is the coefficient before the CH 4 ? (1) What is the coefficient of O 2 ? (2) What is the subscript of C ? (1) What is the subscript for H in the products ? (2) How many atoms of hydrogen are there in the product? (4) How many molecules of CO 2 ? (1)

To balance equations…. Coefficients in front of each chemical formula must be changed. No atoms of any element are created nor destroyed. Bonds are broken and reformed.

In the reaction below, the molecular ratio is 1 CH 4 to 2 O 2 to 1 CO 2 to 2 H 2 O

ION ( SPECIAL ATOMS) a. Atom that gains or loses electrons b. Have an unequal number of e- and p+ c. Have net negative or positive charge d. Very reactive atoms e. Elements on the periodic table are neutral. This means they have the same number of protons and electrons. However, they will always fill there valence shell for stability. Ion

Formation of Compounds by Bonding A.Compounds = 2 or more elements in a fixed ratio B. Have new properties from atoms C.Covalent Bonds = 2 atoms share one or more valence electrons (forms molecules); very strong bond D.Ionic Bonds = transfer of electrons; formed by electrical attraction between two oppositely charged ions. (forms crystals)

Review Equations Look in your packet and review the equations for photosynthesis and cellular respiration. How do they compare to each other? What are the products for each? What are the reactants?

Post-review Questions 1.A student ran tests on a mystery substance and found that is has a definite volume, high density, and flows easily. Which state of matter is it and why? a) It is a solid because it has a definite volume and high density. b) It is a liquid because it has a definite volume and high density. c) It is a gas because it has a definite volume and flows easily. d) It is a liquid because it has a definite volume and flows easily.

1.A student ran tests on a mystery substance and found that is has a definite volume, high density, and flows easily. Which state of matter is it and why? a) It is a solid because it has a definite volume and high density. b) It is a liquid because it has a definite volume and high density. c) It is a gas because it has a definite volume and flows easily. d) It is a liquid because it has a definite volume and flows easily.

2.Which of the following correctly describes the motion of particles in a solid? a)They do not move at all. b)They move rapidly around in random patterns. c) They vibrate in a set pattern. d) They flow easily, but slowly around each other.

2.Which of the following correctly describes the motion of particles in a solid? a)They do not move at all. b)They move rapidly around in random patterns. c) They vibrate in a set pattern. d) They flow easily, but slowly around each other.

3. Analyze the table below. The following symbols each represent one atom of different elements: Which of the above correctly represents a chemical equation showing the law of conservation of mass in a chemical reaction? a)I b)II c)III d)IV

3. Analyze the table below. The following symbols each represent one atom of different elements: Which of the above correctly represents a chemical equation showing the law of conservation of mass in a chemical reaction? a)I b)II c)III d)IV

4. What happens when wood burns with the oxygen in air to form water and carbon dioxide? a)The mass of the products becomes less than the mass of the reactants. b)Most of the mass of the wood is converted into energy. c)More energy is absorbed than given off in the reaction. d)The mass of the wood and oxygen reacted equals the mass of the products.

4. What happens when wood burns with the oxygen in air to form water and carbon dioxide? a)The mass of the products becomes less than the mass of the reactants. b)Most of the mass of the wood is converted into energy. c)More energy is absorbed than given off in the reaction. d)The mass of the wood and oxygen reacted equals the mass of the products.

5. When photosynthesis occurs, carbon dioxide and water produce glucose and oxygen. The balanced equation is 6 CO H 2 O  C 6 H 12 O O 2. How many molecules of C 6 H 12 O 6 are produced when 18 molecules O 2 are produced? a)1 molecule C 6 H 12 O 6 b)2 molecules C 6 H 12 O 6 c)3 molecules C 6 H 12 O 6 d)6 molecules C 6 H 12 O 6

5. When photosynthesis occurs, carbon dioxide and water produce glucose and oxygen. The balanced equation is 6 CO H 2 O  C 6 H 12 O O 2. How many molecules of C 6 H 12 O 6 are produced when 18 molecules O 2 are produced? a)1 molecule C 6 H 12 O 6 b)2 molecules C 6 H 12 O 6 c)3 molecules C 6 H 12 O 6 d)6 molecules C 6 H 12 O 6