Chemical Reactions

What do the letters and numbers mean? The letters are the element symbols The numbers tell how many of that element are present.

MnO4 Ca3N2 LiC2H3O2 Al3S2

What if there are parentheses? They show you have a polyatomic ion The little number multiplies to everything inside of the ( ). Ca(OH)2 = 1 Ca, 2 O and 2 H

Cr(C2H3O2)4 Al2(SO4)3 (NH4)3PO4

What is a chemical reaction? It is the same as a chemical change.

What are the two parts to chemical reactions? The reactants and the products

What are reactants? It is what you begin with.

What are products? It is your final result.

What were the ways we knew a chemical reaction occurred? Creates light or sound Change in temperature Changes color Creates an odor Creates a precipitate Bubbles/creates a gas

What is a precipitate? A solid product from a chemical reaction,

Reading chemical reactions, what are some symbols I may see? + means reacts with or and  means produces or forms (s) is a solid (l) is a liquid (g) is a gas (aq) is aqueous

H2(g) H2O(l) NaCl(s) NaCl(aq)

What does aqueous mean? It means dissolved in water

When a chemical reaction is done, is anything lost or gained? No, all chemical reactions follow the law of conservation of mass.

What is the law of conservation of mass? Mass can never be created or destroyed

What does it mean? What ever mass you begin with in a reaction, you will end with the same mass.

How do we show that we are following the law of conservation of mass? We balance chemical reactions.

What do we use to balance chemical reactions? Coefficients- numbers in front of the compounds 2 H2O is H2O H2O

What does balancing do? Make sure you have the same number of each element on both sides of the reaction.

What are some hints to balancing? Make an inventory Keep polyatomic ions together, if they are on both sides Save hydrogen and oxygen for last. Use pencil

___V2O5 + ___CaS  ___CaO + ___V2S5

___NaNO3 + ___PbO  ___ Pb(NO3)2 +___Na2O

___H2SO4 +___ Al(OH)3___Al2(SO4)3+___ H2O

What are the 5 types of chemical reactions? Synthesis Decomposition Single Replacement Double Replacement Combustion

What is a synthesis reaction? A reaction in which ONE compound is a product. A + B  AB

Sally Joey + 

What is a decomposition reaction? A reaction in which your ONE product breaks down. AB  A + B

 + Billy Betty

What is a single replacement reaction? Where an element replaces one component of a compound to form another compound and an element. AB + X  AX + B

Sally + +

What is a double replacement reaction? You will see 2 compounds as reactants and as products. They just trade what they are paired up with.

+ +

What is a combustion reaction? A compound reacts with oxygen. The two products are always CO2 and H2O. AB + O2  CO2 + H2O

Is there a way to predict the state of matter of the products? Yes, use a chart

On the chart, what does soluble mean? It is an aqueous (aq) compound

What does insoluble mean? It is a solid (s) precipitate

What if it is an exception? It is the other type of compound.

Examples Ca(HCO3)2 LiNO3 Na3P CaCO3 CaCrO4 FeS Ba(OH)2 SrO