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?