TYPES
OF REACTIONS REVIEW
2
NaNO3 + PbO .
Pb(NO3)2 + Na2O
Double Displacement
C2H4O2
+ 2 O2 2 CO2 + 2 H2O
Combustion
ZnSO4
+ Li2CO3 ZnCO3 + Li2SO4
Double Displacement
V2O5
+ 5 CaS 5 CaO + V2S5
DOuble Displacement
S8
+ 8 O2 8 SO2
Synthesis
Organize Your Thoughts
PREDICTING THE PRODUCTS
We want to be able to predict the products for the following reaction types :
- Combustion
- Single Displacement
- Double Displacement
RULES FOR PREDICTING PRODUCTS
OF CHEMICAL REACTIONS
’ Here
are a few important things to remember 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
PREDICTING REACTION
PRODUCTS:
COMBUSTION REACTIONS
’ A hydrocarbon and oxygen
(O2) indicate a combustion
reaction
’ If it is combustion,
then just write H2O and CO2 as products
’ Then, balance the
equation (can be tricky)
’ Examples:
PREDICTING REACTION PRODUCTS:
REPLACEMENT REACTIONS
’ A
metal will not always replace a metal in a compound dissolved in water because
of differing reactivities
’ An
activity series can be used to predict if reactions will occur
’ To
replace a metal, the other metal must be MORE REACTIVE
’ Same
applies for halogens
PREDICTING REACTION PRODUCTS:
SINGLE REPLACEMENT REACTIONS
´ To predict the products: Replace the single element with the corresponding element in the compound
´ A metal will replace the cation in the compound
´ A non-metal will replace the anion in the compound
´ If the element is more reactive than the one it attempts to replace, then the reaction will be spontaneous and exothermic
´ Otherwise, it will not be spontaneous and will be endothermic (NO REACTION)
´ A metal will replace the cation in the compound
´ A non-metal will replace the anion in the compound
´ If the element is more reactive than the one it attempts to replace, then the reaction will be spontaneous and exothermic
´ Otherwise, it will not be spontaneous and will be endothermic (NO REACTION)
PREDICTING REACTION PRODUCTS:
SINGLE REPLACEMENT REACTIONS
PREDICTING REACTION PRODUCTS:
DOUBLE REPLACEMENT REACTIONS
´ If it is double replacement, then the cation
and anions switch places
´ It is helpful to separate each compound
into their cation and anionic parts with their
charges
´ Then switch places, and criss cross the new
compounds to make sure they are the
correct neutral compound formulas
PREDICTING REACTION PRODUCTS:
DOUBLE REPLACEMENT REACTIONS
´ AB and CD are both ionic compounds
´ Separate each compound & write their
charges
´ Switch places and re-write new compounds
´ Example:
´ Balance at the end!!
PREDICTING REACTION PRODUCTS:
DOUBLE REPLACEMENT REACTIONS
´ Not all double replacement reactions will occur
´ In order for a double replacement reaction to
take place:
´ Both of the reactants must be soluble in water
´ If a compound contains at least one of the ions
that is proven soluble, then the compound will be
at least moderately soluble
´ One product must be soluble and one
product must be insoluble
´ The insoluble product is the precipitate that
forms when the reaction takes place
´ Usually a precipitate is a solid, but it doesn't
have to be
SOLUBILITY TABLE
PREDICTING REACTION PRODUCTS:
DOUBLE REPLACEMENT REACTIONS
Predict if a reaction will occur when you combine aqueous solutions
of iron (II) chloride with aqueous sodium carbonate solution.
If the reaction does occur, write a balanced chemical equation showing it.
What is the product of this reaction? K2CrO4 + HCl?
BalasHapusHydrochloric acid is much stronger than chromic acid, the conjugate of potassium chromate. Accordingly, the forward reaction below will be favored:
HapusK2CrO4 + 2HCl ---> 2KCl + H2CrO4
Let me explain again about a single reaction product
BalasHapusA single-displacement reaction is a reaction by which an element replaces another element in a compound. It can be represented generically as:
HapusA + B-C → A-C + B
This will most often occur if A is more reactive than B, thus giving a more stable product.
A and B must be either:
Different metals (hydrogen's behavior as a cation renders it as a metal here), in which case C represents an anion; or
Halogens, in which case C represents a cation.
In either case, when AC and BC are aqueous compounds (which is usually the case), C is a spectator ion.
Copper displaces silver in solution when a copper wire is dipped in a silver nitrate solution, and solid silver precipitates out.
In the activity or reactivity series, the metals with the highest propensity to donate their electrons to react are listed first, and the most unreactive metals are listed last. Therefore, a metal higher on the list is able to displace anything on the list below it.[1] The order of activity for metals, from most reactive to least reactive, is Li, K, Sr, Na, Ca, Mg, Al, Zn, Cr, Fe, Cd, Co, Ni, Sn, Pb, H, Sb, As, Bi, Cu, Hg, Ag, Pd, Pt, Au. Similarly, the halogens with the highest propensity to acquire electrons are the most reactive. The activity series for halogens, from highest to lowest, is F, Cl, Br, I.[2]
Due to the free state nature of A and B, all single displacement reactions are also oxidation-reduction reactions, where the key event is the movement of electrons from one reactant to another.[3] When A and B are metals, A is always oxidized and B is always reduced. Since halogens prefer to gain electrons, A is reduced (from a 0 to −1) and B is oxidized (from −1 to 0) when A and B represent those elements.
A and B may have different charge as ions and therefore some balancing of the equation may be necessary. For example, the reaction between silver nitrate, AgNO3 (which contains an Ag+ ion), and zinc, Zn, forms silver, Ag, and zinc nitrate, Zn(NO3)2 (which contains a Zn2+ ion).
2AgNO
3
(aq) + Zn
(s) → 2Ag
(s) + Zn(NO
3)
2
(aq)
All simple metal with acid reactions are single displacement reactions. For example, the reaction between magnesium, Mg, and hydrochloric acid, HCl, forms magnesium chloride, MgCl2, and hydrogen, H2.
Mg
(s) + 2 HCl
(aq) → MgCl
2
(aq) + H
2
(g)
Komentar ini telah dihapus oleh pengarang.
BalasHapusThe fuel source is most often wood, gasoline, or coal. There are other forms of combustion reactions which are essential to life. ... Burning wood in a fire is an example of a combustion reaction. In the combustion reaction, the carbohydrates in wood combine with oxygen to form water and carbon dioxide.
HapusWhat is the concept of rendemen, and what does it do ?
BalasHapus. The proportion of a valuable substance obtainable from a particular crude material, as of pure crystallizable sugar from a raw sugar.
Hapuswhat is recrystallization???please explainnn unchh!!!!
BalasHapusIn chemistry, recrystallization is a technique used to purify chemicals. By dissolving both impurities and a compound in an appropriate solvent, either the desired compound or impurities can be removed from the solution, leaving the other behind.
Hapuswhat is the formulas of rendement?
BalasHapusHere are some important things to keep in mind when predicting a product: The compound form must be a neutral ionic compound, give an example of a neutral ionic compound!
BalasHapusThe ionic compound is a chemical compound formed by the electrical charge held by each of its constituent atomic ions.
HapusNormally, the ionic compound comprises a positively charged and non-metal charged element negatively charged and forms a crystalline structure.
Kitchen salt - NaCl - is the most common ionic compound found in nature, consisting of a positively charged sodium (metal) atom and a negatively charged (nonmetallic) chlorine atom.
What affects a reaction does not occur perfectly?
BalasHapusConcentration
HapusThis represents the number of substances that react, for the number of particles or reagents very much affect the collision in the reaction so it is very important in determining the rate of reaction. Because the greater the concentration, the more the substances that react and the greater the possibility of collisions.
If the collision between the particles gets bigger, then there is the possibility of the reaction will also be greater, thereby increasing the concentration of reagents trigger the active collision between particles and will cause the reaction rate faster. And vice versa if the reagent concentration is smaller, then the possibility of the collision also smaller so that the rate of reaction will also decrease.
Surface area
Surface area is one of the conditions for the reaction to take place is reagent substances must be mixed and touch each other. In a heterogeneous reagent mixture, the reaction occurs only in the plane of the mixture, called the touchpad. Chemical reactions will take place very quickly if the surface area or plane of the touch is wider too. Because the more surface area the faster the rate of reaction, the opposite the smaller the surface area the smaller the rate of reaction.
The Influence of Pressure
The effect of pressure will be seen on chemical reactions involving gaseous reactants, increasing pressure on reactions involving gas reactants will increase the rate of reaction, this effect will not be seen in reactions involving solids and liquids.
Basically, the effect of pressure on the rate of reaction is similar to the effect of concentration as the pressure increase is usually done to increase the percentage of the gas reacting in the mixed equilibrium, thus increasing the gas pressure is equal to the increase in its concentration and affect the reaction rate.
Effect of Temperature
At high temperatures, the molecular energy increases so that the molecular rate also increases, the increased rate of molecules allows the reaction to take place rapidly, so if the higher the temperature the greater the rate of reactions.
The minimum energy required for a reaction is called activation energy in general when the temperature is added 100 C, then the reaction rate will be twice as large. In other words every temperature rise of 100 C. The reaction rate will be twice as fast.
Catalyst
In chemistry known as two substances that greatly affect the reaction rate of catalysts and inhibitors, the catalyst is a substance that can accelerate the rate of reaction while the inhibitor is a substance that can inhibit the rate of reaction. Slow chemical reactions can be accelerated by adding a catalyst, the catalyst will participate in the reaction process but does not affect the reaction results but only accelerate the rate. The catalyst allows the reaction to take place more quickly due to the changes triggered on the reagent.