Words to Know 1. Combustion a chemical reaction that produces heat and (usually) light

Transcription

1 Learner Activity 2 Worksheet: Chemistry Basics Words to Know 1. Combustion a chemical reaction that produces heat and (usually) light 2. Oxidation combining with oxygen 3. Atom smallest part of something; 4. Molecule a collection of elements; the smallest part of something that contains all the properties. Example: A molecule of water (H 2 O) is the smallest collection of atoms that has the properties of water a liquid with a certain weight. 5. Element a substance made of one type of atom; building blocks for molecules 6. Chemical reaction a set of steps that change a substance. Example: when iron turns to rust a chemical reaction has occurred. 7. Periodic Table a chart of the elements To see the Periodic Table go to: You will visit this site later in the activity. To find the meaning of other chemistry words go to: se%2f101%2fglossary.shtml What happens to an apple when you cut it in half and leave it outside? It turns brown, right? What happens when iron is left outside in the air? It rusts, right? Both of these are examples of oxidation. Fire is a form of oxidation it just happens a lot faster and builds up heat leading to combustion. Before you learn about the chemical reaction that causes fire, you need to know a few basics about atoms and molecules. As you learned above, a molecule of water is written as H 2 O. That means that there are two atoms of hydrogen and one atom of oxygen in each molecule of water. Below is a chart that shows a few of the most common elements and molecules.

2 H Hydrogen O Oxygen C Carbon Ch Methane Na Sodium Cl Chloride NaCl Sodium Chloride Table Salt H 2 O 2 Hydrogen and 1 Oxygen Water CO 2 1 Carbon and 2 Oxygen Carbon Dioxide (di means two) CO 1Carbon and 1 Oxygen Carbon Monoxide (mono means one) Exercise 1 The Periodic Table Print a copy of this worksheet. Go to 1. Click on the box H with a 1 at the top (upper left of the table) Answer these questions about Hydrogen (you will need to scroll down to Description. A. Is Hydrogen usually a gas, a liquid or a solid? B. What color is hydrogen? C. What percent of the Universe is made up of Hydrogen? 2. Find the switch to box at the upper left and type in Oxygen. Click Go! A. Is Oxygen usually a gas, a liquid or a solid? B. What colors can Oxygen be? C. How much of the human body is made up of Oxygen? 3. Switch to Carbon. Click Go! A. Is Carbon usually a gas, a liquid or a solid? B. What color is Carbon? C. What jewelry is made from Carbon? Exercise 2 Counting Atoms

3 Example: If one molecule of water (H 2 O) has 2 atoms of hydrogen and one atom of oxygen, how many atoms of hydrogen and oxygen are in five molecules of water? Think about it like this if there are two hydrogen atoms in one molecule of water, then multiply by 5 to get the number of hydrogen atoms in five molecules of water. So there are ten hydrogen atoms in five molecules of water. Likewise, if there is one atom of oxygen in a molecule of water, multiply by 5 to get the number of oxygen atoms in five molecules of water. There would be five atoms of oxygen in five molecules of water. Your turn. 1. A molecule of copper sulfate is written CuSO 4 Count the atoms in 10 molecules. Cu (copper) S (sulfur) O (oxygen). 2. A molecule of sugar is written C 6 H 12 O 6. Count the atoms in 7 molecules of sugar. C (carbon) H (hydrogen) O (oxygen) Click on the site below to try an interactive quiz on counting atoms. Be sure to take note of how many molecules you are counting. These quizzes are random which means you get different questions each time. If you run into really difficult ones, with parentheses ( ) and exponents (10 5 ) just skip them and answer the ones that are like the examples. Or, take your best guess -you ll still be learning. -formulas-quiz.shtml Exercise 3: Fire Science Words to know:

4 1. vapor the gas form of a substance 2. vaporize using heat to turn a substance into a vapor or gas To find out how fire works go to this Nova site: * Important Notes for the site: To make the site interactive, be sure to use your mouse to follow the white dotted lines with an arrow. Also be sure to go through the Step through this reaction section. In part 3 click Separate Molecules and then drag elements into the boxes to make molecules of water and carbon dioxide. *You will need a program called Flash. You can download it for free at the site. Follow the directions at the site. To find out more about the Fire Triangle go to this website: For more information on fire science visit these websites. Print out the exercise 3 below and answer the questions after you have completed the interactive On Fire activity. 1. What are the three parts of the Fire Triangle? Draw a picture of the Fire Triangle here. 3. When oxidation occurs very quickly it can generate a great deal of. 4. Describe threshold or ignition temperature.

5 5. In the chain reaction section, the hydrogen molecule combined with oxygen to form and was released. 6. What is actually burning when wood or paper is on fire? 7. In the flame experiment, what caused the orange-red color of the candle flame? 8. Describe how a forest fire has all the components of the Fire Triangle.