- Spontaneously is when a chemical reaction continues to occur on its own once it begins.
- Will it continue to occur and how fast will it occur are the questions that determine if a change will occur spontaneously
- Endothermic and exothermic rely on locations of the reactant energy and project energy which indicates whether the overall enthalpy change in either one.
- The energy comes from the bonds that hold the atoms together.
- To increase the reaction time in the MRE heater, we use powdered iron, magnesium and salt water. As well as more surface area and a catalyst.
- A Catalyst speeds up chemical reactions by providing a lower activation energy.
- The Catalyst starts at a higher energy and takes way less time to have a reaction.
In the beginning of this chem talk, it explained what Spontaneous reactions were and the Thermodynamics theories, as well as the kinetics theories. I learned that together, thermodynamics and kinetics help chemists and engineers to design reaction ad processes that are very impactful. There are two factors of spontaneity, firstly, if the change gives of heat energy when it occurs or absorbs heat energy when it occurs. Secondly, is if the reaction results in particles becoming more disordered or less disordered. The rest of the chem talk goes into detail of endothermic and exothermic reactions, as well as energy diagram that help to represent enthalpy. I found this a little confusing, but in the end, it all made more sense. The Diagrams certainly help to understand what is happening in a reaction, but there are a lot of moving parts so it took some time to understand. Overall, this was a helpful Chem talk and I learned a lot.
This Chem talk was centered around Solutions that Conduct electricity and explained electrical conductivity, and the path of electricity in a battery. It began to explain what electrolytes are, they are a solute that forms ions in an aqueous solution. This makes sense to me because runners/ athletes often drink water/ drinks with added electrolites, so the fact that they are in water is understandable. I also learned that for a solution to conduct electricity, the charged particles must be present and the charged particles must be able to move around. Another important topic of electricity, is that since molecules do not form charged particles in solution, solutions made of molecules dissolved in water do not conduct energy, and therefore molecules that do not form ions in solutions are non-electrolytes. With the path of electricity in a battery, I learned that a battery is composed of two half cells, one half cell is where the oxidation occurs, which is called an anode. The other half-cell is called cathode, where reduction occurs. A cool fact I took out of this Chem talk is that electricity only runs spontaneously in one direction in a battery. Finally, it referred to section 4.4, and that the more gap between the two metals, the bigger the reaction will be. I liked this ending because it pulled all the new information together. Overall, this chem talk was a good read and I enjoyed learning about Electrolytes.
This reading began with explaining what a metal is and what properties they have. Something that surprised me was that most of the elements in the periodic table are metals, even though we have learnt that before, it was surprising to hear. Some of these metals are not pure, but it is still an interesting fact. Another cool thing that i learned is that while experimenting with the activities of metals alchemists discovered that some metals react more easily with most metal ion solutions than other metals do and that scientists have developed the activity series from their observations. An important term that was taught was Oxidation-reduction reaction, meaning that an electron was lost during a reaction (oxidation) and that another substance got that electron (reduction). This chem talk was important knowledge for learning how to classify metals and how some metal reactions work.
Both this chem talk combines with the activities we have been doing in class has really improved my understanding of Lewis Dot structures and VSEPR (valence-shell-electron-pair-repulsion Theory). The reading really helped me learn more about bonds and the difference between lone bonds and covalent bonds.It also reviewed what we had learned in class about electron geometry and the names of the 3-D shapes. I appreciate the new information the book has taught me, but I think that without the class activities with the molecules I would be confused. Both of these things have opened my mind to new topics and information in a productive way because it was both visual as well as reading.
In this Chem Talk, the book introduced Stoichiometry. This concept felt pretty foreign at first, but reading on, I saw that it relates to moles, which we have previously learned. I understand that Moles are used for counting large quantities of small things and that In Stoichiometry, moles are used in calculating. This concept was still a little confusing to me, but the experiment provided with the carbon dioxide filling up the balloon helped me a lot. This example really helped clear up my confusion, although I will ask questions in class if I get confused again.
This Chem talk explained the “law of conservation of matter” and explained the historical background about the Conservation of Matter. When one balances chemical equations, they are following the law of conservation of matter, as no matter can be created nor lost in a chemical change. When these equations are written and balanced, the amount on one side must equal what is on the other, even if the atoms are bonded differently. The historical background on the ideas about conservation of matter explains how scientists were struggling with this concept at first, but over time they figured it out. Russia was actually the first to state it explicitly. This Chem Talk was short but informative and I enjoyed reading it.
- A molecules polarity is in correspondence with the electronegativity difference between atoms, meaning the difference in charge between two atoms, which determines how attracted they are to each other.
- The London dispersion force is a very weak intermolecular force.
- The intermolecular forces in water are stronger than those in methane
This chem talk was interesting because it focused mainly on Intermolecular bonds, a topic we as a class have previously covered in fall-winter term. It also discussed Gas’s, Liquids, and Solids and what their bonding looked like. It was cool to read over this because it sparked my thoughts on this topic again and I’m ready to come to class and re-learn and introduce this topic. I did get a little caught up with the last page, but I’m sure that in class we will discuss the topics. I really enjoyed going over the Characteristics of Solids, Liquids, and Gases and i think it was a productive reading. Again, I believe that going over Intermolecular forces of Attraction and Polar Molecules would be really beneficial.
In this Chem talk, it discussed paints and precipitates and color pigments, which was helpful because of the lab we did. When talking about these concepts, I feel as though I have a good understanding of what it all means, but reading more closely it was interesting to discover more about the topics. The rules that chemists follow when using ionic compounds and with mixtures are interesting and new information that I learned. Another interesting thing I learned was what a soluble is, its an ion compound that dissolves in water and when it doesn’t it is “Insoluble”. I think that if artists read this chem talk they would find it very informative because it explains about how paint is made, which is by crushing pigments, and the reaction takes place mainly in water. This Chem talk was one of my favorite because it broke down paints and explained it in chemistry terms.