blog on section 4.7

DesBois Chemistry 

Enthalpy: Exothermic and Endothermic reactions. 

Spontaneous reactions do occur, as chemists would call it. Spontaneous is a change that, once begun, will indeed continues with no need for the input of energy. Thermodynamic is the study of how heat and other forms of energy are involved in chemical and physical reaction. A second theory is now processed called kinetics which is judgmental on the rate of reactions. Kinetics are the study of reaction rates and how they can be affected by variables such as concentration, particle, size, and temperature.  

Heat energy changes: Endothermic and Exothermic reactions. 

Enthalpy change; The change in heat energy for a process that occurs at constant pressure; symbolized by ^H. 

Energy diagram is a graph showing how energy changes during the course of a reaction.  Activation energy is the energy that must be gained by molecules so they can break existing bonds and undergo a reaction. The outer,edoate state that is a combination of reactant and product atoms. 

Catalyst: a substance that provides a lower energy pathway for a reaction which increases the speed of a reaction; it is not consumed (used up) during the reaction. 

 

section 4.6 blog

Electrochemical cells and Half-Reactions 

DesBois Chemistry 

2/5/2018 

In this section, we will determine if a substance will conduct electricity when dissolved in H2O (water). along with the construction or development of a galvanic cell and explain the function of its components. Finally we will learn to describe in depth the effects of adding cells in series.

Electrolytes is a substance or solute in-which produces an electrically conducting solution when dissolved in particular in H2O (water). A polar solvent generally speaking. I am familiar with electrolytes because they are added to water and sports drinks for preventing dehydration  by allowing your body to absorb the water more quickly. Non electrolytes are a solute that does not from ions in a solution, therefore they cannot conduct electric currents. Overall are the total opposite of electrolytes. 

We understand batteries, and we know that they are electrochemical cells, in which they are composed of two half cells. Half cells are in electrochemical batteries, each of two cells that contain and electrode surrounded by a solution. Two half cells are connected by a salt bridge. Salt bridges is used in a laboratory, a device which is used to connect the oxidation and reduction half cells of and electrochemical cell. It allows excess negative ions to pass from the cathode to the anode. Now anodes is the negative battery electrode which removes electrons in an electrical circuit  In an electrochemical cell, oxidation takes place at the anode terminal. Now cathodes are the positive battery elected that relieves electrons in an electrical circuit. In an electrochemical cell, reduction takes place at the cathode terminal. 

ions, which are atoms or molecules that have acquired a charge by either gaining (anion) or losing (cation) electrons. They have a zero net electrical charge. 

Electricity only runs spontaneously in one directions in a battery because of the relative activities of the two metal electrodes used in the half reactions. 

 

section 4.1

2/4/2017

DesBois Chemistry 

Energy And Entropy: Alternative Reaction Pathways.

We will be learning on the concept of applying the engineering design process to scientific and everyday situations. Along with generating the Evolution criteria to compare and evaluate various methods to achieving a goal. And finally the understanding of how energy and disorder change during physical and chemical processes.

Energy And Entropy changes in Chemical reactions. energy can be classified as many different analogies. Many reaction can be understood in terms of energy change by reflecting on your experience with water. For example when adding hear energy to something, we will realize the particles gain the energy. And the particles have more energy than before the hear energy was added. The extra energy in the reaction can also change the bonds that exist between atoms or molecules. 

Whether an energy change is positive or negative, is depended on the perspective in which we view it. Example is energy change from start to end in the chemicals is a positive one. Endothermic, a process which absorbs heat energy and cools its surroundings. The change in energy for the match is negative, in which we know that this is Exothermic, which releases heat energy causing a rise in temperature to its surroundings, a quiet rapid one too. 

As most changes also involve a change in how the particles that make up the matter are organized.

Entropy has a symbol “S”, in which is the disorder of particles (molecules) in a substance based on the number of arrangements given or available too them in a reaction.  

Blog section 3.6

Solubility Rules: Paints and Precipitates.

Kareem Moumina

blog 3.6

In this section we will identify along with predict the properties of double replacement reactions. We will observe reactions in which produce precipitates. Finally understanding how insoluble compounds are and can be used for pigments.

Using solid precipitates as pigments.

\Double replacement reactions. We understand that most reactions in our world take place in water solutions. As cations and anions are combined, water insoluble ionic compounds are then formed. Cations are positively charged ions and Anions are negatively charged ions. This leads us to precipitate, which is the outcome when cations and anions are brought together. Precipitate is an insoluble salt that is formed when two solutions are mixed together, in which the precipitate is indeed an ionic compound because its composed of positive ions and negative ions. An example of a precipitation reaction where a precipitate form is a double replacement reaction which initially is a reaction in which tow ions in two different compounds exchange places to form new compounds. Ions that do not participate in the reaction are called spectator ions. They remain solution before and after the reaction. Net ionic equations are chemical equations for a reaction that lists only those compounds participating the reaction.

Ionic compounds are said to be soluble, meaning it would dissolve in a liquid. And insoluble compound is defined as one that will not dissolve in water, typically producing an aqueous solution of less than 0.001mol/L at room temperature

 

Section 3.4

Physical Properties of metals, 

We will understand the science behind alloys and the construction of brass pennies. The understanding of how metals are affected in the process of making it into an alloy. 

Alloys and their properties. Metallic bonds are formed by the sharing of valence electrons among the atoms in the metal. The electron sea model is a model of the structure of metals that contain valence electrons floating around the metal cations, in which appears to not belong to any one cation. 

Metal catioins, which are positively charged metal ions. In which outer electrons are in constant motion around the metal cations, although not really belonging to any one cation.

Malleability is a very big word toward metals, as it is the property of a material to be hammered into various shapes without breaking. metals when heated soften up, allowing it to be reshaped without breaking. When a metal is in the state of mailability it is rather soft and pliable, not very strong. 

An alloy, which is a mixture or substance that has metal characteristics and contain too or more different elements, although one is a metal . 

Here I will discuss the three properties of different types of steel.

Anealed steel, which is steel that contains fewer carbon atoms between the iron atoms and is a softer, more malleable, and more pliable type of steel. This results as iron is slowly cooled. 

Hardened steel, which is more hard and brittle that results when steel is cooled quickly after being heated from red hot. This causes the carbon atoms to be locked into the crystalline structure. 

Tempered steel, which is heated to an appropriate temperature for a short period of timed then cooled slowly to give it properties of both hardened and annealed steel.

section 2.5

Line Spectra and Electron “Jumps” 

Kareem Moumina

Mr. Desbois       Chemistry. 

we will understand the changes in electron energies in the hydrogen atom, and by using Bohrs model of atom to predict different parts of the hydrogen atom spectrum 

we will be able to identify regions in the electromagnetic spectrum. Niels Bohr theorized that electrons travel in nearly circular paths, which are called orbits which involved the electrons traveling around the nucleus, and simply concept kicks in as the further away the electron is from the nucleus the greater its energy is. Electrons are said to jump between energy levels. Meaning they can never exist in an in between level. 

light, electromagnetic radiation that lies within the visible range. We observed light when hydrogen gas was given a large voltage. visible light is only one part of the electromagnetic spectrum.

electromagnetic spectrum which is the entire range of electromagnetic radiation. at one end of the spectrum are gamma rays, which have the shortest wavelengths although high frequency. we understand that frequency tells us the number of cycles that are being produced in a second. 

your eyes can see only a very small part of the electromagnetic spectrum.

photons which is a quantum or discrete packet of electromagnetic radiation that has a given amount of energy. 

 

 

blog post 1.8

 

Blog post section 1.8

Kareem Moumina

Desbois Chemistry

Flames Tests: Identifying metals

 

The section shows us how to identify different metals ions present in materials and its characteristics and properties when held in a flame.

Ions are electrically charged atoms and they acquire net charge.

Electrons which are subatomic particles that occur outside the nucleus, and the nucleus being a very dense core of the atom that contains neutrons and protons.

When the metal ions are placed in the hot flame their electrons absorb the energy and move to higher energy levels around the nucleas.

Metal compounds are made of atoms that have nuclei surrounded by electrons.

Personally this is very helpful because you can understand a material by just using techniques to identify it. For example, by understanding what each different color meant in the case of dipping wooden splints in different solutions, it’s very helpful to know what is what. Every day we come by these aspects but do not notice them, although they are everywhere, leaves, trees, the ground. It’s very unusual but interesting.

 

 

Section 7

 

Kareem Moumina 

Polymers: Natural and Synthetic. 

polymers which is a substance that is a macromolecule consisting of many similar small molecules covalently bonded together in long chains. 

This section mainly discusses the significance of a polymer based material and its properties which differ from other states of matter that we know about. we will learn the properties and different process in making a polymer based material. 

learn about the poly vinyl alcohol know as PVA which is the bond along with sodium tetra borate (borax). these both make up slime which is a polymer. 

viscosity which resembles in how liquids resist flow. formation of very large molecules from many smaller molecular units is called polymerization. 

we will learn of Polyethylene which is a polymer, which made up of ethylene molecules linked together. 

Polymerization which is the chemical reaction that converts small molecules into large molecules known as polymers. 

portions are natural polymers, and are the basic structural unit of plants and animals. 

Section 1.6

Electrochemical Cells and Half Reactions. 

the section shows us the concepts and methods mainly focused on conducting electricity with metals and how different cells and its components. 

The ability to add cells to a series. We learn how to conduct electricity when dissolved in water also known as determine. we learn how batteries work and how they run out.

the different methods of conduction with different metals through a battery using a battery. We call the particles moving through the wires electrons. 

substances that dissolve in water and conduct electricity are known as electrolytes. Charged particles and compounds which are called ions. their could be different ions as any particles can be charged for example Sodium ions or chloride ions. 

Molecules that do not from ions in solution are non electrolytes. when oxidation takes place its called anode and reduction its called cathode. which is a positive battery electrode and with anode which is a negative battery electrode. 

Kareem moumina 

section 5 blog post Density

Measuring Mass and Volume 

we understand the differences between mass and volume for example a kilogram of led and a kilogram of feather, in which the feather has more density that the lead because of the higher quantity. 

how to measure the different masses with liquid and objects, as we would need to take individual measurements to find the volume.  learning the various methods of calculating mass with the overflow method, in which you would calculate the water, in which an object would be inside, that was spilt out of the container and measure the volume. 

density= mass/ volume. 

 

every material that exists has a mass of some quantity, whether the smallest material or largest, density is the mass of the same volume of each material. 

different symbols and their uniqueness, giving us the precise physical quantities of a specific material. 

we learn how to be very precise in measurements, using different methods, like the coin method or the paper, method and how to read the label on the measurement beaker where the line meets the liquid.