Test 9

7 A and 7B
Monday, 03/16/09

Review

1. Acids and bases are compounds that form certain types of ions when they dissolve in water.
2. Compare and Contrast Acids and Bases.
Acid is a compound that produces hydrogen ions when dissolved in water. Acids are classified as strong or weak depending on how many hydronium result when they dissolve in water. The stronger the acid, the more hydronium ions that form. Acids taste sour.
Bases is a compound that produces hydroxide ions when dissolved in water. Can be classified as strong or weak depending on how many hydroxide ions they produce when dissolved in water. Stronger base greater number of hydroxide ions. Bases have a soapy slippery fell and a bitter taste.

3. When an acid and a base are mixed, they react to form water and salt. When Hydrochloric acid is mixed with sodium hydroxide (base), the salt sodium chloride (table salt) is produced.

4. Compare and Contrast Combustion and Corrosion.

Combustion (burning) is a chemical change that involves a rapid reaction with oxygen. Combustion is the process of chemically combining a substance with oxygen so rapidly that heat and light are produced.

Corrosion (rusting) is a chemical change that involves a slow reaction with oxygen. Corrosion is a slow destructive process, often involving metals that combine with oxygen to form a new compound.

5. In a chemical change, the total mass of the reactants is the same as the total mass of the products.

6. Law of Conservation of Mass: Matter cannot be created or destroyed. Matter cannot be destroyed, only rearranged during chemical reactions. The same number and type of atoms exist after a chemical reaction as existed before the reaction.

7. Chemical reaction is a process in which a chemical change occurs: reactants yield products.

8. Compare and contrast Reactants and Products in a chemical reaction.

Reactant are the substances that are present before the change (starting materials) , the substances that react or change. Products are the new substances formed as result of the chemical change (occurs when substances interact to become a new substance)

9. A chemical equation is a description of a chemical reactions using chemical formulas.

10. Energy is the ability to cause matter to move or change. The energy come from the food you eat which comes from the sun. The energy in food is changes into the energy of motion and body heat.

11. Energy is used to build and repair body cells. Growth and activity depend on storage and releases of energy.

12. All physical and chemical changes require the input or release of energy in some form.

13. Heat is a type of energy; therefore, all temperature changes are essentially transfers of energy.

14. Energy comes in many forms: light, heat, sound, electrical, nuclear, and chemical energy.

15. There are two types of energy: Potential energy and Kinetic energy.

Potential energy is stored energy (potential because it has the potential to make something happen). Kinetic energy is energy of motion (the energy an object has because of its motion).

Answer:

1. List three examples of acids and bases (common and scientific name)

2. Write the chemical formulas of hydronium ions and Hydroxide ions.

3. Describe all the places where chemical digestion takes place. (Story of Digestion p 302).

4. Why we often don't fell hungry when we are afraid or unhappy? explain.

5. Write and explain (identify the reactant and products) three examples of chemical reaction using word equation and chemical equation.

6. Write an word and chemical equation for corrosion and combustion.

7. In the examples above distinguish the elements from the compounds (Question 5 and 6).

8. Which acid is stronger if Acid A produces 20 hydronium ions dissolved in water while Acid B produced 25 hydronium ions dissolved in water?

UPDATED GRADES

T: Test. 10 pts each

H: Homework. 2 pts each

L: Lab reports. 5 pts each

SC: Science Fair: 20 pts.

P: Presentation. 10 pts.

7A and 7 B: 55 pts accumulated.

8A: 52 pts accumulated.

8B: 54 pts accumulated.

8th Grade Study Guide

Test 9

8A and 8B: 04/03/09

All following statements are True.

1. Forces applied to structures may be classified as either tensile, compressive, or shear.

2. Structures are compressed by their own weight.

material that respond to the removal of stress by returning to their original shape are said to behave elastically.

3. Compressive force is a force that preses a material together.

4. Deflection is the amount that a material bends when a force is applied to it.

5. Shear force is the force that causes bending or twisting in a material.

6. Tensile force is a force that causes material to stretch.

7. Spider's web is stronger than copper or wood.

8. The strength of any material can be increased by changing its shape.

9. A cantilever is a beam that is fixed at one end.

10. An arch provides more strength against a vertical load than does a simple beam.

11. An arch transforms vertical loads into lateral ones..

12. A dome is closely associated with the arch. A dome is essentially a rotated arch.

13. Bridges are classified according to their structures.

14. A truss is a framework of connected planks or steel bars that add strength and support to a structure.

15. Each major period of history is characterized by its own unique architecture.

16. Modern architecture is often based on models from the past.

17. Architectural design is often based on available technology.

18. Structures that fail may do so because of unsound design, chemical changes, or physical changes.

19. Materials used in construction have characteristic chemical and physical properties that determine their durability and strength. Changes in theses properties can cause failure.

20 Elasticity determines a material's reaction to different forces.

Study ALL the question from the presentations.

Compare and contrast: Ancient Greece, Ancient Rome, Medieval Europe, Renaissance and Moderns Civilization.

7th Grade Study Guide

Test 8

7B: 05/03/09

7A: 06/03/09

Study Guide.

T or F (All the following statements are True)

1. Chemical are uniform substances with predictable properties.

2. Each chemical has certain chemical and physical properties that distinguish it from other chemicals.

3. Chemical changes are not easily reversed.

4. Chemical changes form new substances, but physical changes do not.

5. Properties are characteristics that distinguish one substance from another.

6. All chemicals can be classified as either elements or compounds.

7. Around 100 elements exist naturally on Earth.

8. The periodic table is a chart in which all known elements are organized according to their chemical properties.

9. All matter in the universe is made up of elements, either alone or in different combinations.

10. Atomic number is the number of protons in the nucleus of an atom.

11. The number of electrons around the nucleus must be equal to the number of protons in the nucleus.

12. Atoms consist of a nucleus composed of protons and neutrons.

13. The nucleus is surrounded by a cloud of electrons.

14. A neutron has almost the same mass of a proton, but an electron has much smaller mass.

15. The columns of the periodic table are referred to as groups, and the rows are referred to as periods.

16. There are 18 groups in the periodic table, numbered from left to right.

17. The elements within a group share more properties with each other than they do with any of the other elements. Ex: elements in group 1 are metals, while elements in group 18 are gases.

18. There are 7 periods.

19. The periodic table arranges the elements in order of increasing atomic number in horizontal rows, with elements that look and act alike in vertical columns.

20. The chemical formula of water is H2O.

Answer.

1. Definition of: Reactants, products, word equation.

2. Describe water (at least 5 properties) that does no confuse it with other liquids, such as oil, alcohol, vinegar etc.

3. List: the six elements found in all living things. (with the symbol); The three most abundant elements on the Earth's crust.

4. How many protons are found in then nucleus of Helium, Carbon, Nitrogen, and Oxygen? how many electrons?

5. Write the chemical equation and word equation for the reaction of hydrogen and oxygen to form water, and the reaction of carbon with oxygen to form Carbon dioxide. (S131).

GRADES III PARTIAL

8A: 22 pts accumulated

8B: 24 pts accumulated

T: test; H: Homework

T: Test; L: Lab reports.

Test 8 Sciences 7th

Monday, February 23

Study Guide.

T or F. All the following statements are True.

No two objects can occupy the same space at the same time.

Weight is measured in Newtons

The gram is the base unit for measuring mass. The liter for measuring volume.

A change of state is a physical change.

Boiling point is the temperature at which a liquid rapidly becomes a vapor (gas).

Melting point is the temperature at which a solid changes to a liquid.

Freezing point is the temperature at which a liquid changes to a solid.

Condensation is when a gas becomes liquid.

Chemical are uniform substances with predictable properties.

Each chemical has certain chemical and physical properties that distinguish it from other chemicals.

Bubbles, heat, light, and color changes may indicate a chemical change. Chemical change are not easily reversed.

Chemical change form new substances, but physical changes do not.

Examples of physical changes are: breaking, dissolving, boiling, evaporating, or freezing.

Atoms, the basic units of all the elements, are not the smallest form of matter.

Answer.

1. What is matter? S86

2. What is molecule? S87

3. What is mass? S90

4. What is weight? S90

5. Compare and contrast mass and weight (at least 2 differences and 1 similitude)

6. What is density? S92.

7. List the four statement of the atomic theory. S100

8. What is an atom? S100

9. What is electron? S101

10.What is a proton? S102

11. What is a neutron? S102.

12. Answer the five questions of Checking Your Understanding on p S105.

13. State the temperatures at which oxygen, aluminum, water and hydrogen would be liquid and gas. p242.

Exercises. (show all work)

1. Find the weight of your parents (both) and siblings (all).

2. A block of pine wood has a mass of 120 g and a volume of 300 ml. what is the density of the wood?

3. Find the density of the objects measured in Lab 7: "Mass and Volume". Lemon, baseball ball, rock, and egg. which objects would you expect to float on water, why?.

Solve the study guide on your notebook. Write question and answer of print the study guide and paste it in the notebook.

TEST 8 SCIENCES

Monday, February 16

8th A y B

Study Guide

ANSWER:

1. What is gravitational force (gravity)?

2. What is weight?

3. What is mass? how do they differ (mass and weight)?

4. Describe the first two laws of Isaac Newton that describe motion and its related forces.

5. Describe the Gravitational Theory.

6. What is Friction (frictional force)? List 3 examples of friction (name the surfaces involved)

7. List three ways we can reduce friction.

8. List three harms of friction.

9. What is inertia?

10. Relationship between inertia and mass.

T or F

1. A large mass exerts a stronger pull than does a smaller mass at the same distance. True (gravitational attraction depends on their masses and the distance between them (objects)).

2. Objects with different masses accelerate downward at the same rate. True. (more force is needed to accelerate a larger mass, and because of its greater mass, the pull of gravity acting on the larger mass is greater than the pull of gravity acting on the small mass).

3. Acceleration and force are directly proportional, as force increases, acceleration increases. True.

4. Inertia is not a force, is a quality of an object that causes it to resist any change in its state of rest or motion. True.

5. Friction occurs when surfaces rub against each other. True.

6. Friction is greater when motion is starting than when it is continuing. True.

7. Friction is greater for heavier weight. True.

8. The greater the mass, the greater the inertia, that is the greater the tendency of an object to remain as it is and the greater the force needed to alter the object's state. True

Practice

1. Find the Force (weight) of an object if its mass is 220 Lbs.

2. Find the acceleration of a 75 kg skater that pushes off from a wall with a force of 200 N.

3. Fin the mass of an object with a force of 15 N.

4. Find the weight of your parents and siblings on Earth.

5. Find the weight of your parents and siblings on Mars and Moon.