3rd Class

  Agua

1.     Oxygen - atom in water that attracts electrons more strongly

2.     Polar - a molecule with an uneven distribution of charge

3.     Water - an example of a polar molecule

4.     Hydrogen bond - attraction of a hydrogen for a more negatively charged atom such as oxygen or nitrogen

5.     Cohesion - attraction between molecules of the same kind

6.     Adhesion - attraction between molecules of different kinds

7.     Capillarity or capillary action - tendency of water to rise in a narrow tube due to adhesion and cohesion

8.     Molecular Motion - Molecular motion is how the molecules move and the energy associated with the movement affects the physical properties of a chemical. Molecules can move in three ways, transitional, rotational, and vibrational.

2nd Class

Basic Chemistry

During our second class, we review few basic chemistry topics, such as elements, compounds, and bonds between atoms.

Atomic number = # of protons = number of electrons

Atomic mass number = protons + neutrons

Atomic mass number – Atomic number = neutrons

Elements VS Compounds:

 

1. Elements: Elements are substances that cannot be separated into simpler substance.

2. Compounds: A compound is a substance formed when two or more elements are chemically joined.

 

Compound VS Molecule

1 A molecule consists of two more atoms, which can be the same or different types of atom, that are linked by a chemical bond. A molecule of H2 or O2 is still a molecule, but not a compound.

2. A compound is usually a molecule as well. To be a compound, it has to have two different types of atoms, such as H2O.

3. Some compounds like NaCl are not molecules because they are linked together in a crystalline structure, rather than being molecularly bonded.

Isotope:

Isotope: one of two or more atoms with the same atomic number but with different numbers of neutrons. Some isotopes are very useful in the field of chemistry and biology. One example would be radiation. Radiation from certain isotopes can be used to detect and treat cancer while also kill bacteria.

Nonpolar covalent VS Polar covalent VS Ionic bonds.

1. A nonpolar covalent bond is a bond where electrons are shared equally between two atoms.

2. A polar covalent bond is a chemical bond where the shared electrons spend more time closer to the nucleus of the more electronegative atom.

3. In an ionic bond, the electrons are completely transferred from one atom to another rather than shared.

Milk and Food Coloring Lab

Milk and Food Coloring Lab 

Why the milk and food coloring interacted the way they did?

  Today in Biology class we tried to figure out why the milk and food coloring interacted the way they did. The experiment is fun, and we get to see a myriad of pretty interaction.

  First, my hypothesis of this experiment is that the soap, which contains () dissects the fat molecule in the milk and it causes the interaction. In this experiment, the independent variable is the food color, and the dependent variable is the milk, and the control would be no dish soap. The soap accelerates the diffusion of the fat molecules in the milk. Soap attract water and oil, so as the soap march into the milk, it rearrange the fat molecules and the food coloring molecules gets push around which cause the interaction that shown in the video.

Material:

Whole milk

Skim milk

Orange juice

Coffee

Water

Ajax

Food coloring

Toothpick

Two containers

Procedures:

1.     Pour milk to fill out a glass

2.     Add several drops of food coloring

3.     Take a toothpick covering completely with Ajax

4.     Use the toothpick to dip around the water

5.     Redo step 2,3,4 but using different orange juice, coffee and different kinds of milk.

6.     Try to do the entire experiment without the soap 

(Whole Milk vs. Skim Milk)

1.     From the picture, we can see that the food coloring reacts stronger and faster in the whole milk container instead of the skim milk container. We had done this 2 more times, and we got the same results

   

         Then we want to prove that the fat molecules determine the movement of the food coloring.  Therefore,   we add food coloring in orange juice, coffee, and water, but we do not add any soap into the container. 

(Orange Juice vs. Coffee)

       

      (Water)  

    From the picture, it shows that in the same amount of time. The food coloring reacts more in the orange than it is in the coffee. Also the food coloring had barely interacted with the water. 

(Orange Juice VS Coffee)  

(Whole Milk VS Skim Milk) 

   Therefore, my conclusion is although it would take a long time to do it, but the food coloring would diffuse in the milk eventually without the soap. Also, it is the fats that make the difference, and more fats mean more interaction. Since more fat would have more molecules.