Chemical Reactions

 What does the symbol Δ in a chemical equation mean?

• heat is supplied to the reaction
• a catalyst is needed
• yields
• precipitate

In a decomposition reaction:

• the reactants are generally two ionic compounds in aqueous solution
• energy in the form of heat or light is often produced
• one of the reactants is often water
• the reactants are usually a metal and a nonmetal

The chemical equation, Cr  +  Fe(NO3)2  →  Fe  +  Cr(NO3)3, is an example of which type of reaction?

• double-replacement
• combustion
• decomp.
• single-replacement

Which of the following are decomposition reactions?
1. CH4 (g) + O2 (g) →  CO2 (g) + H2O (l)
2. CaO (s) + CO2 (g)  →  CaCO3 (s)
3. Mg (s) + O2 (g) →  MgO (s)
4. PbCO3 (s) →  PbO (s) + CO2 (g)

• 2 and 3
• 4 only
• 2, 3, and 4
• all are decomp. reactions

What type of reaction is FeS + 2HCl --> FeCl2 + H2S

• synthesis
• decomp.
• combustion
• replacement

A chemical reaction that absorbs energy in the form of heat is described as 

• exothermix
• endothermic
• unbalanced
• combustion

The substances listed on the left side of a chemical equation are the

• products
• coefficients
• percipitates
• reactants

What group contains the most elements?

• transition metals
• metals
• non-metals
• metalloids

every chemical reaction involves a change in

• concentration
• mass
• energy
• state

The number placed below an element's symbol in a chemical formula is called a

• product
• coeffecient
• subscript
• reaction