Chapter 8 test...A chemical reaction has not occured if the products have the same chemical properties as the reactants. Which observation does NOT indicate that a chemical reaction has occured?change in total mass of subtances. A solid produced by a chemical reaction in solution that seperates from the oltion is called a precipitate. After the correct formula for a reactant in an equation has been written, the formula should not be changed. What is the small whole number that appears in front of a formula in a chemical equation? a coefficient. To balance a chemical equation, it may be neccessar to adjust the coefficients. According to the law of conservation of mass, the total mass of the reacting substances is alwas equal to the total mass of the products. A chemical equation is balanced when the same # of each kind of atom appears in the reactants and in the products. In an equation, the symbol for a substance in water solution is followd by (aq). A chemical formula written over the arrow in a chemical equation signifies a catalst for the reaction. When the equation Fe3O4+Al yields Al2O3+Fe is correctl balanced, what is the coefficient of Fe?3. Which coefficients correctly balance the formula equatin NH4No2(s)ieldsN2(g)+H2O(l)?1,2,2. Which coefficients correctly balance the formula equation CaO+H2OyieldsCa(OH)?1,1,1. What is the balanced equation for the combustion of sulfur?S(s)+O2(g)yields4H2O. Which equation is not balanced?2H2+O2yieldsH2O. The equation AXyieldsA+X is the general equation for a decompostion reaction. IN what kind of reaction does one element replace a similar element in a compound? Single-replacement reaction. In what kind of reaction does a single compound produce two or more simpler substances? decomposition reaction. The equation A+BXyields AX+B is the general equation for a single relacement reaction. In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds? double replacemetn reactions. The reaction 2Mg(s)+O2(g)ields2MgO(s) is a synthesis reaction. The reaction Mg(s)+2HCl(aq)yields H2(g)+MgCl2(aq) is a single replacement reaction. The reaction 2HgO(s)yields 2Hg(l)+O2(g) is a decompostion reaction. The reaction 2KClO3(s)yields2KCl(s)+3O2(g) is a decompostion reaction. The decompostion of a sustance by an electronic current is called electrolsis. When heated, a metal carbonate decomposes into a metal oxide and hydrogen. Oxides of active metals, such as CaO, react with water to produce metal hydroxides. When binar compound decomposes, what is produced?2 elements. many metal hydroxides demopose when heated to yield metal oxides and water. When heated, metallic chlorates decompose into metallic oxides and chlorine. An insoluble gas that forms in a double replacement reaction in aqueos solution bubbles out of a solution. Predict the product of the following reaction: MgO+CO2yields...MgCO3. An element in the activityseries can replace any element below it on the list. If metal X is lower than metal Y in the activit series. than metal X replaces ions of metal Y in a solution. Chapter 10... The volume of a gas is 5.0L when the temp. is 5.0C. If the temp. is increased to 10 without changing the pressure. what is the new volume?5.1L. A 70L sample of gas at 20C and 600.mm Hg expands to 90L at 15C. what is the new gas pressure?459mm Hg. At