Module # 3 Supporting Standards Chemistry Module # 3 Supporting Standards

Elements and Compounds You need to know the difference between an element and a compound. An element begins with a capital letter. Examples: He, Cl, O A compound is two or more different elements (capital letters). Examples: NaCl, HeO O2 would not be an example of a compound because it only has 1 element. Readiness All element symbols begin with a capital letter and end with lower cased letters if this applies. A common misconception that can occur is that Co (Cobalt) is confused with CO (carbon monoxide). Notice the difference. CO has 2 capital letters meaning that it has 2 different elements, which makes it a compound. On the other hand, Co is only element because it only has 1 capital letter. Also, in chemistry Cl is chlorine. That is a “C” and lower cased “l”. Students will often think that the “l” is an “I”.

Metals, Nonmetals, Metalloids Metals are located to the left of the bold stair step on the periodic table. They have a high luster, which means shiny. They are very malleable, which means bendable, and are good conductors of heat/electricity. Nonmetals are located to the right of the bold stair step on the periodic table. They have low luster, which means they are dull. They are not malleable. They are poor conductors Metalloids touch the bold stair step on two sides. (Exception: Aluminum) The have properties of both metals and non metals. Some make good semi-conductors in electronic devices like the element Silicon. Readiness Some examples of metals include aluminum, sodium, nickel, and copper. Some examples of non metals include chlorine, oxygen, and sulfur. The metalloids are boron, silicon, germanium, arsenic, antimony, tellurium, and astatine.

Metals, Non Metals, Metalloids Readiness

Calculating Density Mass Volume Remember density explains how loose or packed the atoms are in the substance. You need to know how to calculate density and then identify an unknown substance based on its calculated density. Locate the density formula on the science chart. Find mass and volume in the data table or story problem. Remember to put mass in the house. After you have calculated the density, use the table to find your number and figure out the name of the substance. Readiness Density is used to describe how atoms are arranged in a substance. For example, nickel is more dense than oxygen at room temperature. Often, density is used to describe a specific property of a substance. Every type of substance has a unique density no matter its size. For example, if a ship is made of pure iron, its density would the same as an iron nail. Though they are different sizes, they will still have the same density. Density is a proportional relationship between mass and volume. So, the reason we divide mass by volume is to calculate the density. Mass Volume

Organic Compounds Organic compounds contain carbon and other elements such as hydrogen, oxygen, phosphorous, nitrogen, or sulfur. CHNOPS Ex: Glucose = C6H12O6 is an organic compound because it contains carbon, hydrogen, and oxygen. Readiness A good point to remember is that if it has Carbon, it will most definitely be an organic compound. CHNOPS is a mnemonic to help remember the organic elements that make organic compounds. Each letter stands for an organic element. C= Carbon, H= Hydrogen, N= Nitrogen, O= Oxygen, P= Phosphorous, S= Sulfur

Physical and Chemical Changes In the digestive system, there are many physical and chemical changes. Physical Chemical Teeth breaking down food Movement of food through the esophagus Churning of food in stomach Exit of food through the anus Enzymes break down food in mouth HCl acid breaking down food into chyme in stomach Nutrient exchange with the small intestine. Readiness The mechanical smashing of teeth together to break food into smaller pieces is a physical change. After this, enzymes salivase and amylase are released in the mouth to break down starch into a simple sugar (glucose). This is a chemical change. From there, the esophagus moves the food into the stomach by peristalsis (muscle contractions). This is a physical process. In the stomach, HCl acid turns the bolis of food from the esophagus into chyme. This is a chemical process. The food then travels into the large intestine where waste will exit the body through the anus.

Balanced Chemical Equations Mass is neither created nor destroyed in a chemical reaction. You will always have the same mass before the reaction as you do after the reaction. This is the Law of Conservation of Mass. Readiness When a chemical reaction occurs no matter is ever lost, it simply transforms into different matter with properties different from the original matter. In chemical reactions, the atoms simply get rearranged to create a new substance. The mass will always be the same. Sometimes mass might escape into the air as a gas, but it is still there. This is the biggest idea in chemical reactions to remember.

Law of Conservation of Mass Readiness After the reaction occurs and because it is a closed system where no gas can escape, the mass should be the same at 196.5 g. When the reaction takes place what will the mass on the scale read?

Counting Atoms Record the number of atoms of each element represented in each of the following. Example: H2O = H = 2; O=1 C12H22O11 3CO2 2Na NaOH 2CaCO3 Readiness To count the number of atoms in a molecule or compound: Simply identify each element Look at the subscript (little number) next to each element. This will tell you how many atoms there are of that particular element. The little number only goes with the element to its left. If there is no subscript to the right of the element, then it is understood that there is 1 atom of that element. If there is a big number in front of both elements, like 3CO2, then the coefficient 3 applies to both carbon and Oxygen. So, in this case, there are 3 molecules of CO2 or 3 total carbon atoms and 6 total oxygen atoms.

Is the equation balanced? Reactants Products Readiness To recognize if an equation is balanced or unbalanced, you first have to count the number of atoms on the left of the arrow (yield sign) and compare with the number of atoms on the right side of the arrow (yield) sign. If there are the same number of atoms on either side of the arrow, the equation is balanced. If there are different number of atoms for each element on either side of the arrow, then the equation is unbalanced.