Synthesis and Decomposition

Synthesis and Decomposition

First, we learned about the definition of a chemical change. A chemical change results when substances chemically react to produce a new compound(s). Next, we learned about  the processes of synthesis and decomposition. Synthesis is when two or more reactants react chemically to from one product. Decomposition is when one reactant splits into several compounds or substances. Synthesis and decomposition reactions are technically the same processes, and they are just flipped vice versa.  Also, we learned how to use the ember from a burning splint to determine what gases are being released.  If carbon dioxide is being released, then the ember will fade. If oxygen is released, the ember will continue glowing without exploding. If hydrogen is being released, then the ember will explode.  We also learned how to predict the products of synthesis and decomposition reactions while using phase symbols:

Phase symbols: s-solid, g-gas, l-liquid, aq- aqueous 

This is what happens when you put a splint with ember when oxygen gas is being released. http://physical-science.tripod.com/id25.html

Acids, Bases, pH, pOH, etc.

Acids and Bases

In this lesson, we learned about the definitions of acids and bases. The definitions of acids and bases are determined separately by two very different theories. The Arrhenius theory states that the acids have a low pH and that bases have a high pH on the pH scale. It states that acids have a high hydrogen concentration, whereas bases have a high hydroxide concentration. We also learned that if you add water to a base or acid, the pH of the solution will head to be neutral (7). If a substance has a neutral pH, like water, then the substance also has a neutral pOH (measures hydroxide). We also learned a formula chain that helps us find the pH, pOH, hydrogen and hydroxide concentrations of a substance or a solution. The formula chain is shown below. 

This formula chain can help us find the concentration or pH and pOH of a substance. 

We also learned that acids are sour, react best with metals, and they are slimy. Bases are not as slimy, bitter, and do not react with metals. The more acidic a solution is, the better it is at conducting electricity.

Gas Laws Reflection

Opinion on Gas Laws

This week, our chemistry class learned about gas laws. This standard covers on the topic of what is the definition of an ideal gas is. Basically, an ideal gas is a type of gas that can never be changed into any other state of matter. Although this idea was created, there is actually no ideal gas (imaginary gas) that can be found in the universe because all gases can change into different states of matter according to different atmospheric pressures and temperatures. We also learned how to use the ideal gas law equation to help solve for unknown variables including pressure, volume, number of moles, and temperature. The ideal gas law equation is in the form of: 

pV=nRT

where P is the pressure, V is the volume, N is the number of moles, R is the ideal gas constant, and T is temperature. 

This equation can also help us find relationships between two or three variables like finding how changing the pressure of a gas affects the volume of a gas.  Overall, this standard was a little confusing because some of the rules for a gas to become ideal is counter-intuitive because every gas does not follow that rule or kinetic theory.  I also cannot wait to learn more or be interested about stoichiometry since this is supposed to be the hardest subject that tortures every student. Plus I'd like a good challenge!