Chemistry Notes PDF

SI system: Length-meter Time-second Amount of substance-mole (mol) Electric current- ampere (amp) Temperature- kelvin mass - kilogram Matter: a physical substance that hass mass and occupies space Atomic number: the number of protons in a nucleus always equals the number of electrons in an unioniz...

SI system: Length-meter Time-second Amount of substance-mole (mol) Electric current- ampere (amp) Temperature- kelvin mass - kilogram Matter: a physical substance that hass mass and occupies space Atomic number: the number of protons in a nucleus always equals the number of electrons in an unionized atom. All atoms that have the same number of protons (the atomic number) are the same element. Atomic mass: mass number= protons+neutrons *find the neutrons by subtracting the protons from the mass number* Isotopes: different versions of the same element (varaible based on the number of neutrons). Isotope number is the total number of protons and neutrons combined. Average atomic mass formula: for each isotope- percent it naturally occurs (divided by 100) X the mass number and then add all of those together for each isotope. For example chlorine has two isotopes, chlorine 35 and 37. 35 occurs 75.77 percent of the time and 37 occurs 24.23 percent of the time so our equation for finding the average atomic mass of chlorine would be 0.7577 X 35 + 0.2423 X 37. And our answer would be 35.49 with lines up with the average atomic mass we see on the periodic table. Conservation of mass law: matter can neither be created nor destroyed. All atoms going into a chemical reaction are present in some form in the product. Small loss of mass equals released energy. Reminder: maintain the same number of significant digits in the answer as the original value. How to balance equations: write the unbalanced equation. List the elements involved, count the atoms on both sides, balance the oxygen atoms first, balance coefficients from there. Limiting and excess reagents: complete and balance the chemical equations, convert reagent to moles, determine which reagent is limiting, use the mole ratio to determine the moles of the product from the limiting reagent, determine the mass of the products (or vol etc). Stoichiometry: moles to moles is solved by doing moles given multiplied by the required mole coefficient divided by the given mole coefficient. Moles to mass is solved by doing moles times molar mass. Percent yield is the percent of the theoretical yield actually produced, it is calculated by dividing the actual yield by the theoretical yield and multiplying by 100. Actual yield is the amount produced and is calculated by multiplying he percent yield by the theoretical yield divided by 100. theoretical yield is the potential product that may be produced and it is calculated by dividing actual yield by percent yield and multiplying by 100. Ionic compounds are solid at room temperature. Covalent compounds are formed between 2 nonmentals and can be any state at room temp. The shapes i need to know and their angles are: bent/angular (