Chemistry students typically experience difficulty in predicting the products of chemical reactions. With practice, however, the process becomes progressively easier. The first step identifying the type of reaction involved is usually the most difficult. The primary reaction types students encounter are displacement, acid-base and combustion. They are easily identified if the tell-tale signs are known. Displacement reactions involve two ionic compounds with cations and anions, such as sodium sulfate, in which sodium (Na) is the cation and sulfate (SO2) is the anion. Ionic compounds always consist of a metal and a nonmetal or polyatomic (multiple-atom) anion. Decomposition reactions involve a single compound breaking into two or more compounds. Acid-base reactions must involve an acid (identified by its chemical formula that begins with “H,” such as HCl). Combustion reactions involve hydrogen or a hydrocarbon (such as CH) reacting with oxygen (O2).
If we start with only one reactant, the reaction taking place is probably a decomposition reaction. To predict the products of such a reaction, see what happens if the chemical breaks into smaller, familiar products such as water, carbon dioxide, or any of the gaseous elements.
All chemical reactions can be classified into one of six categories:
1. Burning Reaction
2. Reaction Synthesis
3. Decomposition Reactions
4. Single Displacement Reaction
5. Acid-base Reaction
6. Double displacement reaction
Burning Reactions
The combustion reaction is when oxygen combines with other compounds to form water and carbon dioxide. These reactions are exothermic, which means they produce heat.For example naphthalene combustion reaction.
C10H8 + 12 O2 -> 10 CO2 + 4 H2O
Reaction Synthesis
The synthesis reaction is when two or more simple compounds combine to form one more complex compound. These reactions appear in a general form:
A + B -> AB
One example of a synthesis reaction is a combination of iron and sulfur to form iron (II) sulfide:
8 Fe + S8 -> 8 FeS
Decomposition Reactions
The decomposition reaction is the opposite of the synthesis reaction - the complex molecule is broken down to make a simpler molecule.These reactions appear in a general form:
AB -> A + B
One example of a decomposition reaction is electrolysis of water to make oxygen and hydrogen gas:
2 H2O -> 2 H2 + O2
Single Displacement Reaction
This reaction is when one element alternates with another in a compound. These reactions appear in a general form:
A + BC -> AC + B
One example of a single displacement reaction is when magnesium replaces hydrogen in water to make calcium hydroxide and hydrogen gas:
Ca+2H2O->Ca(OH)2+H2
Double displacement reaction
This is when the anions and cations of two different molecules switch places, forming two completely different compounds. These reactions appear in a general form:
AB+CD->AD + CB
One example of a dual displacement reaction is the reaction of lead (II) nitrate with potassium iodide to form lead (II) iodide and potassium nitrate:
Pb(NO3)2+2KI->PbI2+2 KNO3
Acid-base Reactions
This is a special kind of double displacement reaction that occurs when acids and bases react with each other. H + ions in acid react with OH⁻ ions in the base, causing water formation. Generally, the product of this reaction is ionic and water salts:
HA+BOH->H2O + BA
An example of an acid-base reaction is the reaction of bromide acid (HBr) with sodium hydroxide:
HBr + NaOH -> NaBr + H2O
What the meaning of rendement and the relation with ksp/Qsp?
BalasHapusRendement is the yield refers to the amount of reaction product produced in a chemical reaction. The marine product can be saturated, precisely saturated and unsaturated. The solubility product is generally denoted by Qc and the method of calculating Ksp is the product of the concentration of dissolved ions in a soluble salt. The difference is that the Qc value shows the solubility product in the unconfirmed state whether the solution is unsaturated, precisely saturated or saturated (precipitated) while Ksp is the product of the concentration of ions decomposed in a soluble salt at the maximum saturated). To determine the state of the solution, we must know the value of Ksp first.
HapusIf the value of Qc <Ksp then the solution is not saturated.
If the value of Qc = Ksp then the solution is exactly saturated.
How to identify the chemical reaction result?
BalasHapus´Here are a few important things to
Hapusremember when predicting products:
´The compounds form must be neutral
ionic compounds (which means you’ll be
paying attention to their charges)
´You do NOT carry subscripts from the
reactants to the products.
´You always balance your equation LAST
how can predict product from chemical reaction?
BalasHapusThe first step identifying the type of reaction involved is usually the most difficult. The primary reaction types students encounter are displacement, acid-base and combustion. They are easily identified if the tell-tale signs are known. Displacement reactions involve two ionic compounds with cations and anions, such as sodium sulfate, in which sodium (Na) is the cation and sulfate (SO²) is the anion. Ionic compounds always consist of a metal and a nonmetal or polyatomic (multiple atom) anion. Decomposition reactions involve a single compound breaking into two or more compounds.
HapusWhat is the benefit of rendement on this experiment?
BalasHapusYields can also be calculated by measuring the amount of product formed (typically in the crude, unpurified product) relative to a known amount of an added internal standard, using techniques like gas / liquid chromatography, or NMR spectroscopy. A yield determined using this approach is known as an internal standard yield.
HapusGive examples Double displacement reaction?
BalasHapusAgNO3 + NaCl → AgCl + NaNO3
HapusHere's another example:
BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2 NaCl(aq)
In your explanation of "the reaction that occurs may be a decomposition reaction" then what is a decomposition reaction?
BalasHapusIn a combination reaction, a substance is formed as a result of chemical combination, while in a decomposition reaction, the substance breaks into new substances.
HapusGive an example of a decomposition reaction?
BalasHapusFor example, this method is employed for several analytical techniques, notably mass spectrometry, traditional gravimetric analysis, and thermogravimetric analysis. Additionally, decomposition reactions are used today for a number of other reasons in the production of a wide variety of products, some of which may be surprising. One of these is the explosive breakdown reaction of sodium azide [(NaN3)2] into nitrogen gas (N2) and sodium (Na). It is this process which powers the life-saving airbags present in virtually all of today's automobiles
HapusWhat are the requirements of acid-base reaction?
BalasHapus