Coefficient In Chemical Equation

Coefficient In Chemical Equation

Two 17
17Copper nitrate does not exist as molecules; copper and nitrate are both ions in the1compound, and are attracted to each other, but do not join together.The formulaindicates that in a sample of copper nitrate, there will be two nitrate ions for everycopper ion.In equations, it is sometimes convenient to show such compounds asif the ions were joined together.CHEMICAL EQUATIONSWHAT BALANCING AN EQUATION MEANSWHAT IS A CHEMICAL EQUATION?A chemical equation is a way of representing a chemical reaction in symbolic form.

For example, when hydrochloric acid is added to sodium hydroxide, the equation readsThe symbols for the eactants (the substances that are mixed) are written on the left, whilethe symbols for the products (the substances that are formed in the reaction) are written onthe right.

The arrow indicates that the materials shown on the left are changes to thematerials shown on the right.A chemical equation shows not only what the reactants and products are, but it shows alsohow much of each reactant combines to form how much of each product.For example:This equation can be interpreted to read that three atoms of copper react with eightmolecules of nitric acid to form three "molecules" of copper nitrate, two molecules of nitric1oxide (NO), and four molecules of water.It can also be interpreted to read that three molesof copper react with eight moles of nitric acid

to form three moles of copper nitrate, twomoles of nitric oxide (NO), and four moles of water.Moles will be explained in a latersection; the important thing to understand now is that the correct number (coefficient) infront of each formula is critically important.In the first example above, the formulae have no coefficients.The absence of a coefficientmeans 1 (one).

Thus, one mole of sodium hydroxide reacts with one mole of hydrochloricacid to produce one mole of sodium chloride and one mole of water.Other information that may be included in an equation is the state (solid, liquid, gas, orqueous solution) of each reactant and product.

This additional information is not alwaysincluded in an equation, but sometimes it may be useful, or even vitally necessary.Symbols used are: (s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous (dissolved in water).The equation shown above may be rewritten:18BALANCED CHEMICAL EQUATIONSA balanced chemical equation is one in which for each kind of atomic symbol, the numberon the left side of the equation equals the number on the right side.There is one Na, one Cl, one O, and two H on each side.Notice with the H, on the left side2there is one H in NaOH and one H in HCl.

On the right, they are shown as two H in HO.3On the left there are three Cu, eight H, eight N, and twenty four O.Each HNO has one H,one N, and three O.The coefficient, 8, multiplies everything in the formula.

On the right32there are three Cu; six N in 3Cu(NO) plus two N in 2NO, total eight N; eighteen O in3233Cu(NO) (three in NO, doubled to six by the subscript 2 outside the brackets), then2tripled to eighteen by the coefficient 3) plus two O in 2NO plus four O in 4HO, totaltwenty four.Sometimes it is easier to check the balancing of an equation by counting the numbers ofcompound ions on each side of the equation, provided that none of the compound ions hasbeen changed (as in the example above, where some of the nitrate ions change to NO).For example:24On the left there are three sulfate ions (one sulfate in each HSO, times the coefficient 3).On the right there are three sulfate ions ((SO) times the subscript 3; there is no coefficient243to the Al(SO), so the value of the coefficient is 1).HOW TO BALANCE EQUATIONS BY INSPECTIONThere are three basic approaches to balancing chemical equations:a) by inspectionb) by half-equationsc) by oxidation states.Only the first of these will be treated in this section: the other two will be explained in latersections.Balancing a chemical equation by inspectionmeans no more than to look at theequation and see by looking what coefficients are needed
coefficient in chemical equation
Chemical Equation
Name Date. _ 16 Relating Moles to Coefficients of a Chemical Equation PRE-LAB DISCUSSION The mole is defined as Avogadro's number (6.02 x 1023) of particles. (
Balancing Chemical Equations
Provided by Tutoring Services 1 Balancing Chemical ... the amount of an element on one side of the equation ... coefficient of 3 so that there will be a total ... (
Balancing Equations Challengebalancing Equations Challenge
Part B: Label the chemical equation using PRODUCT, REACTANTS, SUBSCRIPT, COEFFICIENT, and YIELDS. O2 What element does the O represent? _____ CO 2 … (
.For a balanced equation to be written, it is necessary that the reactants and products beknown.This requires that the writer of the equation have a sufficient knowledge ofDescriptive Chemistry, that is, of that branch of Chemistry that describes the properties andreactions of various elements and their compounds.The purpose of this section is to explain the balancing of equations.A little DescriptiveChemistry will be presented, however, to cover a few common kinds of chemical reactions.19i).NEUTRALISATION OF ACIDS AND BASES.An acid is a substance with "acid" in its name, and its formula usually starts with H.2434Examples: sulfuric acid, HSO, hydrochloric acid, HCl, phosphoric acid, HPO.2(Water, HO, is sometimes considered to be an acid, but here will be taken as an"exception" to the rule about acids.)A base is defined here as a compound with a metal ion, and either oxide or hydroxide.2Examples: sodium hydroxide, NaOH, calcium hydroxide, Ca(OH), copper oxide, CuO,3zinc oxide, ZnO.

Ammonia gas, NH, is also a base: when it dissolves in water, it reactswith the water; the solution is sometimes called ammonium hydroxide.

The ammonium4ion, NH, has a positive charge, and resembles a metal in some of its properties.+An acid plus a base always gives a alt and water.A alt is any compound of a metal (orammonium) ion with a negative ion other than oxide or hydroxide.Examples: zinc23432iodide, ZnI, sodium phosphate, NaPO, copper nitrate, Cu(NO), calcium carbonate,3CaCO, sodium chloride, NaCl.Sodium chloride is one of the most common salts in theworld, so is often called common salt, or just alt for short.When an acid and base are mixed, the metal (or ammonium) of the base and the negativeion from the acid form the salt, while the hydrogen of the acid combines with the oxide2or hydroxide from the base to make hydrogen oxide (HO) or hydrogen hydroxide(HOH), which are both water.EXAMPLES:Insp
Balancing chemical equations
H Provided by Tutoring Services 3 Balancing Chemical Equations and start again with new coefficients.Manysemester will require trial and error.For example, you might not automatically be able to see how the following eqn can be worked out.

The reason some of these elements are in parentheses is because they are diatomic compounds that are made up of more than 1

is the NO (nitrate) ion.

These ions are negative because they have gained a negatively charged electron thus making them thus losing negativity.

This bonding of negative and positive ions has formed ionic indicated by the 2 outside the parenthesis.

A drawing might help you see > The Cu is easy to count, but with the elements are harder to count.Since the OH in Cu(OH)applies to both the H and the O, so there are 2 O atoms and 2 H atoms in this molecule.Dont forget to add both the 2 O atoms from the Cu(OH) molecule and the 3 atoms from

molecule together for the total number of O atoms on the left of the eqn.Now

molecule, there are 2 N atoms and 6 O atoms.

When you have an element with a subscript enclosed by parentheses with another subscript, multiply them together, and then multiply by the coefficient of the entire molecule.

Cu1 1 O5 7 H3 2

N1 2 H H H H by Tutoring Services 5 Balancing Chemical Equations In combustion rxns, first balance the C and H then balance the O last.In any rxn, combustion or not, it is best to revise the coefficient of the ONow there are more O atoms on the right than the left, so the coefficient of Othe right, but what coefficient multiplied by you cant figure it out in your head, use an

= 7 to balance the eqn.

The last step is to multiply each molecule by the denominator of the fraction to make Also, the coefficients in a balanced eqn should be the smallest whole numbers possible.For example, the coefficients of the following eqn could all be reduced by 2.

C 2 1 O2 3 H6 2

Start Finish C 2 2 O2 7 H6 6 Provided by Tutoring Services 7 Balancing Chemical Equations

+ 3HBr

(NH Ca* Information for this handout was obtained from the following .
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