Chapter 15: Water

Today we learned about Water, which is the most important resources of Earth. In chemistry, H2O also known as Water which consisting 3 atoms. Oxygen atoms form a covalent bond with hydrogen atoms. We know that oxygen has a greater electronegativity than hydrogen. So that oxygen creates partial negative charges and hydrogen creates partial positive charge. Surface tension is the inward force pull to tend the aruface area of liquid. Molar mass of water is 18g/mol but boiling point is 100 degree celcius. Hydrogen bonding gives high surface tension, low vapor pressure, and high boiling point.

Chapter 14.4: Diffusion and Effusion

We learned about the Graham’s Law which is diffusion and effusion. Definition of diffusion is the tendency of molecules to move toward areas of lower concentration until it ùiorm throughout. Perfume can be an example, when you open the perfume bottle, we can be able to smell, the molecules in perfume can evaporate and diffuse, which like spreading out through the air in the room. Another process involves movement of molecules is effusion, which is like a gas that can escape through a small hole in its container. The rate of effusion of a gas is inversely proportional. The gas of lower mass can diffuse and effuse faster than gas of higher molar mass. How fast it moves, it depends on the molar mass.

Chapter 14.4: Dalton’s Law of Partial Pressure

Today we learned about the Dalton’s Law of Partial Pressure. It states that at a constant volume and temperature. Pressure total is equal the sum of all the gases, the partial pressures of component gases. The partial pressure is the contribution each gas in a mixture that makes the total pressure to exerted by gas. The fraction of the pressure exerted by gas does not change as the total pressure changes.

Chapter 14.1: Properties of Gases

Gases are very easy to compress, or even squeeze into a smaller volume. When it collides with substances, the impact forces the molecule of another substances closer together. The compression of gas absorb the engery of the impact. The space between the particles in a gas helps it easy to compress. The amount of gas, the temperature and the factors are the ones that affect the gas pressure.

Chapter 13: State of Matters

In chapter 13, we learned about the properties and assumptions of gases, and factors that affect the gas pressure. Gases are composed with small particles, hard spheres. It has insignificant volume which compared with the distance to the containers in liquid and solid. The motion in gas is very rapid, random and constant, it collides with each other to another particles. All collisions in gas are elastic that transferred from one to another without loss. The temperature and KE are proportion that when temperature increases, the KE should be decreases, but when temperature decreases, KE needs to be increases

atom

The Atom has cloud and nucleus, cloud has electrons, nucleus has protons and neutrons. It shows on the Periodic table, when each Element, they have the atomic number, it is protons, and using the formula to find neutrons. Everytime the atom is neutral, electrons and protons are equal.  The Bohr Model shows about how atom’s energy change when atom absorbs. And the hydrogen is only have one electron. The electrons in an atom cannot exist between energy levels. The Bohr Model provided results with experiments using hydrogen atom. But it needs more electrons to have a good result of doing it.

Atom

Today in class, I learned about Atom. What is atom? There are 3 states of atoms: electrons, protons and neutrons. Electrons are negatively charge , protons are positively charge and neutrons is neutral. Protons and neutrons are located inside the nucleus, electrons are located outside the nucleus. Democritus’s Atomic Philosophy and Dalton’s Atomic Theory. The radii of most atoms is 5 × 10−11 m to 2 × 10−10 m.

State Of Matter

In Chemistry today, we learned about the states of matter, and the changes. First of all, there are 3 states: solid which is definite shape, and volume, not compression, and it compacts; liquid is definite volume, no definite shape, fairy compressible and it’s a molecule; gas is indefinite shape, indefinite volume, it’s compressible, its movement is very constant and random. There are 2 changing in state of matters: Sublimation is a change from a solid to gas; Deposition is from gas to a solid.

Significant Figures

Today in class, we learned about how to determine Significant Figures. First of all, I learned how to know which is significant figures by looking at the zeros that between the nonzero digits, for examples: 4005 – has 4 significant figures, or also 500.89 has 5 significant figures. Also, zeros at the end of each numbers which is to the right of a decimal point are significant. Example: 470.00 has 5 significant figures, or 20.02 has 4 significant figures. And for Rounding measurements, example: 264.832 => 2.648 x 10^2. And the rules of addition, substraction, multiplying and dividing.

SCIENTIFIC NOTATION.

Today, we all studied Scientific Notation together. I learned that the long number could write into a easy and small number using Scientific Notation. I also learned that in Scientific Notation, every number that is greater than 1 is positive. And I learned about the rules for dividing and multiplying.