* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Balancing Equations Notes
Safety data sheet wikipedia , lookup
Spinodal decomposition wikipedia , lookup
Determination of equilibrium constants wikipedia , lookup
Computational chemistry wikipedia , lookup
Chemical equilibrium wikipedia , lookup
Transition state theory wikipedia , lookup
Registration, Evaluation, Authorisation and Restriction of Chemicals wikipedia , lookup
Host–guest chemistry wikipedia , lookup
Chemical element wikipedia , lookup
Rate equation wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Chemical bond wikipedia , lookup
Debye–Hückel equation wikipedia , lookup
Molecular dynamics wikipedia , lookup
History of chemistry wikipedia , lookup
Extended periodic table wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
Stoichiometry wikipedia , lookup
Atomic theory wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
Balancing Equations Chemical Equation: a way to represent chemical reactions on paper. Animation http://www.chemistry.ohio-state.edu/betha/nealChemBal/ The law of conservation of matter states matter cannot be created or destroyed but can change from one form to another. Therefore, equations must be balanced! Atoms can be neither created nor destroyed in an ordinary chemical reaction, so there must be the same number of atoms on both sides of the equation. These numbers are found in a chemical equation: Subscripts - The small numbers to the lower right of chemical symbols. Subscripts represent the number of atoms of each element in the molecule. How many atoms of each element are there in one formula unit of ammonium sulfide? Ammonium sulfide is (NH4)2S How many atoms of each element are there in one formula unit of barium nitrate? Barium nitrate is Ba(NO3)2 Coefficients - The large numbers in front of chemical formulas. Coefficients represent the number of molecules of the substance in the reaction. How many atoms of each element are there in three formula units of barium nitrate? 3Ba(NO3)2 Check for Diatomic Molecules - H2 - N2 - O2 - F2 - Cl2 - Br2 - I2 If these elements appear by themselves in an equation, they must be written with the subscript 2 Please write these diatomic molecules on you blue ion sheet. Chemical equations give information in two major areas. First they tell us what substances are reacting and what substances are being produced. Reactants Products 2H2 + O2 2H2O What are the reactants? What are the products? Second, the coefficients of a balanced equation tell us in what ratio MOLE the substances react or are produced. 2H2 + O2 2H2O How many moles of water are produced? How many moles of hydrogen are needed? How many moles of oxygen are needed? How do we balance equations? Balance equations by changing coefficients Never by changing formula subscripts Steps: 1. Write all reactants on the left and all products on the right side of the equation arrow. Make sure you write the correct formula for each element. 2. Use coefficients in front of each formula to balance the number of atoms on each side. 3. Multiply the coefficient of each element by the subscript of the element to count the atoms. Then list the number of atoms of each element on each side. 4. It is often easiest to start balancing with an element that appears only once on each side of the arrow. These elements must have the same coefficient. Next balance elements that appear only once on each side but have different numbers of atoms. Finally balance elements that are in two formulas in the same side. Balance these equations: _____Zn + ______HCl _____ZnCl2 + _____H2 _____KClO3 _____KCl + _____O2 _____S8 + _____F2 _____SF6 _____Fe + _____O2 _____Fe2O3 _____C2H6 + _____O2 _____CO2 + _____H2O More Practice http://www.fordhamprep.com/gcurran/sho/sho/worksheets/worksht81b.ht m