Chapter 8: Chemical Reactions
Empirical formula of a compound from combustion analysis data
1.) Determine the masses of C and H from the masses of CO2 and H2O. 2.) Determine the mass of O, if present, by subtracting the masses of C and H from the total mass of the initial sample. 3.) Determine the number of moles of each element in the compound, and use the results as subscripts in a chemical formula. 4.) Convert the subscripts in the formula to whole numbers, by dividing each by the smallest subscript.
Steps to calculate the mass of product formed
1.) Determine the moles of reactants (divide the mass of each reactant by its molar mass) 2.) Determine the amount of product formed from each reactant, using the appropriate mole ratios. 3.) Identify the limiting reactant as the reactant that produces the smallest amount of product. 4.) Multiply the number of moles of product formed (from the limiting reactant) by the molar mass of the product to find the mass.
Steps used in a combustion analysis to determine the empirical formula
1.) The mass of original sample is determined by weighing. 2.) The sample is heated in the presence of oxygen. 3.) The CO2 and H2O produced by the combustion are trapped separately. 4.) The mass of each product is determined. From the masses of CO2 and H2O collected, the percent composition and empirical formula are calculated.
Identifying the limiting reactant
1.) The reactant that produces the least amount of possible product is the limiting reactant. 2.) Calculate the amount of product that could be formed from each reactant. 3.) Calculate the molar masses of any reactants for which a mass has been given.
Give the balanced equation below, determine the moles of HCl required and the mass of AgCl formed from the complete reaction of 18.3g of Ag2S. Ag2S(s) + 2HCl (aq) -> 2AgCl (s) + H2S (g)
10.6g of AgCl are formed 0.148 mol HCl are required
Combustion
A reactant rapidly reacts with O2(g) most commonly.
Composition reaction
A single product is formed from two or more reactants.
Decomposition
A single reactant forms two or more products.
Decomposition reaction
A single reactant produces two or more products.
Examples of Halogen Compounds
BrCl HF KI
Combination
Two or more reactants combine to form a single product.
A chemical equation is a statement using chemical __ that express both the identities and the relative __ of the reactants and products involved in a chemical or physical change formulas, quantity
formulas quantity
Metallic Character
increases from top to bottom in a group and left to right in a period.
Of the elements listen, selected all that typically appear as diatomic molecules.
Iodine Nitrogen
Which of the following actions are permitted in balancing a chemical equation?
Multiplying all coefficients by a common factor. Inserting coefficients before the formulas of reactants and products.
Group 1A
Some of the alkali metals can combine with oxygen to form compounds with the formulas M2O, M2O2, and MO2 Hydrogen is not included in the classification "alkali metals" The alkali metals are reactive with water and oxygen.