Chapter review
Chapter review
Matter is anything that has mass and occupy space. The smallest particle of matter is referred to as an atom. An atom is the basic substance of the matter. An atom consists of; tiny subatomic substance. These substances are; proton, electron, and neutron. The protons are positively charged; electrons are negatively charged, and neutrons have no charge. The atom is divided into two parts, the center that consists of the neutrons and proton and the outer part which consist of the electrons.
An atom has different properties; a physical property can be seen and observed without changing its composition chemically. A chemical property of the matter describes how the substance reacts. An atom forms an ion by either losing or gaining an electron in the outer most energy level.
Stoichiometry is branch of chemistry that deals with the reaction of elements. A chemical reaction takes place when there is a transfer of electron from one element to another. When the chemical reaction occurs between the elements they do so in equal whole number ratios. To achieve this, you must balance the chemical equation so that you can be able to obtain the product of the reactions. The ions that do not change their state are called the spectator ions. A chemical reaction may be altered by adding a catalyst. The catalyst does not take place in the reaction.
Reaction of an aqueous solution
Solution are acidic, basic, or neutral, an acidic solution is a solution that has a hydrogen ion. A basic ion has a hydroxyl ion in the solution. The concentration of the solution is the number of moles of substance per 1000ml of the solution. There are different factors that determine the solubility of the solution. These include; the temperature, concentration of the solution, the nature of solvent and others.
There are different reactions involving solutions. These are precipitation reaction, and acid-base reactions. The precipitation reaction is a reaction that involves the formation of a solid that cannot dissolve. Precipitation reaction is used in the preparation of insoluble salt. The acid-base reaction occurs when the hydrogen ion from and acid react with the hydroxyl ion from the base to give water and salt.
Stoichiometry problems in solutions include acid-base titrations and solving titration problems. The acid base titration is used to determine the concentration of the unknown solution using a solution of known concentration. In solving titration problem, we must be able to write a balanced equation of the reactions.
The gas laws
There are different gas laws. These include Boyle law, Charles law, combined gas law, Avogadro law. The Boyle gas law states that the pressure of a gas at constant temperature is inversely proportional to the volume the gas occupy. The Charles law states that for a fixed pressure of a gas the volume of a gas is directly proportional to the volume the gas occupy. The Avogadro law states that one mole of a gas occupy 22.4 litres of gas. The combined gas laws combine the Boyle law, Charles law and the Avogadro law.
The motion of a gas is influenced by the temperature of the place, at low temperature, the gas molecules moves slowly while at high temperature the gas move at high speed. This is because the kinetic energy of the gas particles.
Electron configuration
In an atom, the electrons are located at the energy level around the center. These energy levels are called the configurations. The atom is not reactive if the outer energy level has 8 electrons. That is the electron in the last energy level is full. This energy level are said to have a neon electron configuration. Electrons with same number of electrons in the outermost energy level are grouped in the same group on the periodic table while electrons with the same number of energy level are grouped in the same period of the periodic table. The ionization energy of an atom is the energy required to form an ion by losing or gaining at electron in the outermost energy level. The electron affinity is the power of an atom to attract an electron to the outermost energy level. The electron negativity is the power of the element to gain an electron to form an ion.
The groups
The hydrogen is the atom the can form an ion by either losing one of its outer most electron or by gaining the outer most electron. Alkali metals are the elements in group one. They react by either losing it one of the outer most energy level. They include; lithium, potassium, sodium and other. Their reactivity increase as we go down the group. This is because the easy in losing the outer most electron increases as we go down the group. The alkaline earth metals are elements that form their ions by losing two electrons in the outer most energy level. Thy include beryllium, magnesium, etc. The transitional metals are the elements that are formed between period three and group four in the periodic table. They can form the ions by having different charges.
References
Holmes, D., Moody, P. & Dine, D. (2011) Research Methods for the Biosciences. Oxford
Ruxton, G. D. & Colegrave, N. (2011) Experimental Design for the Life Sciences, 3rd Ed. Oxford
