Download chemical reaction

A chemical reaction
is a process one or more substances are transformed into
another substances.
Physical change
- color change
- solid formation (precipitation)
- gas release (evolution of a gas
- heat exchange (evolution or absorption of heat)
chemical equation
is an expression of a chemical reaction by using symbols
and formulas.
In a reaction the starting substances are called reactants
reactants
products
the substances formed in a reaction , are called products.
reactant1 + reactant2  product(s)
(g)= gas
(I)= liquid
(s)= solid
(aq)= aqueous (water) solution
Balancing Chemical Reaction
Because atoms are neither created nor destroyed in any reaction, a chemical
equation must have equal number of atoms of each elements on each side of
the arrow. Stoichiometric balancing of a chemical reaction means adjusting the
coefficients for the reactants and products in equation.
CH4 + O2
 CO2 + H2O
Stoichiometric coefficients are the numbers placed in front of formulas in a chemical equation.
Left side contains
Right side contains
1C
1C
4H
2H
2O
3O
The balanced reaction is,
CH4 + 2 O2
 CO2 + 2 H2O.
2 H2 (g)
2 molecules H2
two moles of H2
4 grams of H2
reacts with
+
O2 (g)

2 H2O (s)
1molecules O2
2 molecules H2O
one mole O2 and
reacts with
32 g O2
and
two moles H2O is produced.
36 g H2O
is produced.
how many moles and grams of H2O are produced by burning 2.72 moles H2
a) in an excess of O2
b) with 1 mol O2
Ballance the following reactions
N2H4 + N2O4
NaOH + CO2
CaO + P4O10
 N2 + H2O
 Na2CO3

+ H2O
Ca3(PO4)2
limiting reactant
In a chemical reaction one reactant is completely consumed while some
amount of the other reactant/s) remains. The amount of products is limited
by that reactant consumed. The reactant that is completely consumed in a
chemical reaction limits the amounts of products formed, is called limiting
reactant or limiting reagent.
• Determine the limiting reactant and the mass of product
when 1.20mol of Sb and 2.40mol I2 mixed?
Sb + I2  SbI3
Sb:243
I:127.0
what mass of AgBr is formed when a solution containing 3.45 g of KBr
is mixed with a solution containing 7.28 g AgNO3?
KBr + AgNO3
 AgBr + K+ + NO3-
Consider the following reaction:
Na3PO4 (aq) + Ba(NO3)2(aq)
 Ba3(PO4)2(s) + NaNO3 (aq)
Suppose that a solution containing 3.50 grams of Na3PO4 is mixed with a
solution containing 6.40 grams of Ba(NO3)2. How many grams of Ba3(PO4)2 can
be formed?
Yields of chemical reactions
theoretical
yield.
actual yield.
The percent
yields
The quantity of product that is calculated to form when all
of the limiting reactant is consumed in a reaction is called
the theoretical yield.
The amount of product actually obtained is called the
actual yield.
The percent yields is the ratio actual yield to the
theoretical yield times 100%
Soru:
Fe + O2  Fe2O3
Reaksiyonunda 11.2g Fe yeteri kadar oksijenle reaksiyona girdiğinde 10.0g Fe2O3 oluşuyor.
Reaksiyonun teorik verimi, gerçek verimi ve yüzde verimini hesaplayınız. Fe :56 O:16
Methyl tert-butyl ether (MTBE, ), a substance used as an octane booster in
gasoline, can be made by reaction of isobutylene with methanol. What is the
percent yield of the reaction if 32.8 g of methyl tert-butyl ether is obtained from
reaction of 26.3 g of isobutylene with sufficient methanol?
Na3PO4 (aq) + Ba(NO3)2(aq)
 Ba3(PO4)2(k) + NaNO3 (aq)
When 3.50 Na3PO4 reacts ewith 6.40 gram Ba(NO3)2 how many grams of Ba3(PO4)2 will produce?
• Soru: 3,00g etilenamin CH3NH2, 0,100g H+ ile reaksiyona girdiğinde
2,60g CH3NH3+ oluştuğuna göre reaksiyonun gerçek verimi ve
yüzde verimini hesaplayınız.
• CH3NH2, + H+
•
→ CH
3NH3
CH3NH2, : 31,06
CH3NH3 :32,07
Reactions in Aqueous Solution
Precipitation
Reactions
Acids, Bases, and
Neutralization
Reactions
Oxidation–Reduction
(Redox) Reactions
Çözelti:
Homogeneous mixtures are called solutions
solvent
solute
nonelectrolyte
Substances such as sucrose or ethyl
alcohol, which do not produce ions in aqueous solution, are
called nonelectrolytes.
electrolytes
Substances such as NaCl or KBr, which dissolve in water to
produce conducting solutions of ions, are called electrolytes.
strong electrolytes,
weak electrolytes.
Compounds that dissociate to a large extent
(~100%) into ions when dissolved in water
are said to be strong electrolytes,
compounds that dissociate
to only a small extent are weak electrolytes.
Mol number
m
n = --------MA
Molarity
n
M= ------V
mol/L
m
d = ---------V
gr/mL
density
Diluting Concentrated Solutions
Minitial x Vinitial = mol number = Mfinal x Vfinal
Minitial x Vinitial = Mfinal x Vfinal
Find the molarity of a solution that 23.4g of Na2SO4 was dissolved in water and diluted to
250.0ml
Na2SO4: 142
calculate the molarity of H2SO4 solution when we dilute 50.0 mL of a
solution of 2.00 M H2SO4 to a volume of 200.0 mL.
Q1
How can you prepare 500ml 0.10 M H2SO4 solution from 3.0M H2SO4?
Q2
How would you prepare 500.0 mL of 0.2500 M NaOH solution starting from a
concentration of 1.000 M?
What is the final concentration if 75.0 mL of a 3.50 M glucose solution is diluted
to a volume of 400.0 mL?
Q3
Reactions in Aqueous Solution
Precipitation
reactions
Are the reactions, an insoluble solid is formed, the solid
product is called as a precipitate.
Ag+(aq) + Cl-(aq) → AgCl(s)
solubility rules
Soluble salts
salts of 1A groups (Na, K, Li,) and NH4+ are soluble
all nitrates, acetates and perchlorates are soluble
NO3 (Nitrat), CHCOO- (asetat) ,ClO4 (perklorat)
all chlorides (halogens) are soluble except (AgCl, Hg2Cl2, PbCl2)
most sulfates (SO42+ ) are soluble except (Sr SO4, Ca SO4 , Ba SO4 , Pb SO4 )
Cl-, Br-, I- SO42Li+, Na+, K+, Rb+, Cs+ NH4+ NO3-
ClO4-
CH3CO2-
solubility rules
Slightly soluble
all OH- hydroxides are insoluble except those of 1A group (Na, K, Li,) and NH4+
all sulfides S2- are insoluble except those of 1A group (Na, K, Li,) and NH4+
all carbonates are insoluble except those of 1A group (Na, K, Li,) and NH4+
All PO43- are insoluble except those of 1A group (Na, K, Li,) and NH4+
CO32-, PO43- OH-, S2-
• What will happen if Na2CO3 and CaCl2 solutions are mixed ?
• What will happen if CuSO4 and NaNO3 solutions are mixed ?
Acids and Bases
Asit
Baz
Have a sour taste,
-Have a bitter taste,
dissolve metals such as zinc and
carbonate minerals
-Have a slippery feel
-change color of litmus to blue,
change color of litmus to red
-React with dissolved metal to form
prepiciate
Asit ve Bazlar
Asit- Baz Tanımları
Arrhenius Acid-Base Definition (1884)
An acid is a substance that contains hydrogen and dissociates to
produce Hydrogen ion in water : H+
HCl(aq)  H+(aq) + Cl-(aq)
A base is a substance that contains the hydroxyl group and
dissociates to produce Hydroxide ion : OH –
NaOH (aq)  Na+ (aq) + OH -(aq)
Neutralization is the reaction of an H+ ion from the
ion from the base to form water, H2O
H+(aq) + OH-(aq) <=> H2O(l)
acid and the OH -
Asit ve Bazlar
Asit- Baz Tanımları
Brønsted-Lowry Acid-Base Definition (1923)
An acid is a species having a tendency to donate an H+ ion.
HCl
+
H2 O

Cl–
+
H3 O +
A base is a species having tendency to accept an H+ ion.
NH3 + H2O

NH4+
+
OHIn the Brønsted-Lowry perspective, one species donates a proton and another
species accepts it: an acid-base reaction is a proton transfer process.
Asit ve Bazlar
The Lewis acid-base definition :
A base is any species that donates an electron pair
An acid is any species that accepts an electron pair.
B
+
H+

B - H+
Asit ve bazların Kuvvetliliği
Kuvvetli Asit
Zayıf Asitler
Strong Acids; An acid that completely
ionized in water, is called as a strong
acid
Weak acid is an acid that partly ionized
in water.
HCl H+ + Cl-
CH3COOH +H2O CH3COO- + H3O+
HCl, HBr, ve HI
HNO3, H2SO4, HClO4 gibi Oksiasitler
HF . HCN , H2S
HClO, HNO2, ve H3PO4
Organik asitler
(RCOOH), CH3COOH C6H5COOH
Asit ve bazların Kuvvetliliği
Kuvvetli baz
Zayıf baz
A base that completely ionized in water,
is called as a strong base
A weak base is a base that partly
ionized in water.
NaOH Na+ + OH -
NH3 +H20  NH4+ + OH -
M2O or MOH,
M= 1A(1) metalleri (Li, Na, K, Rb, Cs)
MO or M(OH)2,
M = Group 2A metalleri (Ca, Sr, Ba) [MgO and
Mg(OH)2
Amonyak (:NH3)
Aminler
(RNH2, R2NH, R3N), CH3CH2NH2, (CH3)2NH,
(C3H7)3N, C5H5N
• pH
The pH is defined as the negative logarithm in base 10, of the
hydronium ion concentration
pH = - log[H3O+]
• The pOH is defined as the negative logarithm in base 10, of the
hydroxyl ion concentration
pOH = - log[OH-]
• pH of a neutral solution = 7.00
• pH of an acidic solution < 7.00
• pH of a basic solution > 7.00
Oxidation reduction reactions
•
Chemical reactions which involve involve electron transfers from one atom to
another, are called oxidation-reduction or redox reactions.
•
•
•
•
Oxidation is the process in which the oxidation number of atoms increase,
Reduction is the process in which the oxidation number of atoms is decreased
Oxidation is the loss of electrons by an atom reduction is the gain of electrons
D
Fe2O3(k) + 3 CO(g) → 2 Fe(k) + 3 CO2(g)
Fe3+ --- metallic iron
CO(g)---- Carbon diokside
Fe3+
+ Cu+ →
Fe2+ + Cu2+
Fe3+ + e- → Fe2+
Cu+ → Cu2+ + e-
Oxidation states
•
•
•
•
•
•
•
•
Oxidation states (oxidation numbers) reflect, in general way, how electros are
involved in compound formation.
the oxidation state(O.S) of an atom in the pure (uncombined) element is 0.
The total (sum) of the oxidation state of all the atoms in a molecule or
formula unit is 0.
For an ion total of the oxidation state is equal to the charge on the ion.
In their compounds the alkali metals (1a groups Li, Na, K, Rb, Cs, Fr) have
an +1 oxidation number. 2A group metals +2.
In its compounds, the oxidation state of hydrogen is +1. but in NaH BeH2 it
has OS of -1
O.S. of fluorine is –1. halogens have generally O.S of -1 when they combine
with H and metals.
In its compounds oxygen has an oxidation state of –2.
Balancing Redox reactions
1- Split the equation into two half equation
2- Balance the two half equation same number of electrons must
appears in each half equation
• balance the atoms of element being oxidized or reduced
• balanve oxidation number by adding electrons
• balance charge in acidic solutions add H+ add OH in basic
solutions
• balance hydrogen by adding H2O
3- combine the two half equation eliminate electrons
• Soru: Fe2+ + MnO4- →
• Soru: Cl2
Fe 3+ + Mn2+ balance in acidic medium
+ Cr(OH)3 → Cl- + CrO42- balance in basic medium
• Soru: C2H5OH + Ce4+ → CO2 + Ce3+ balance in acidic medium
Titrasyon
•
Titration is a procedure for determining the concentration of a solution
by allowing a carefully measured volume to react with a standard solution
of another substance, whose concentration is known. By finding the volume
of the standard solution that reacts with the measured volume of the first
solution, the oncentration of the first solution can be calculated.
• equivalent point
The point that all reactants are consumed, Stoichiometric mol numbers of both
reactants are equal.
•
an indicator a compound that change its color around equivalent point. such
as phenolphthalein, is colorless in acidic solution but turns pink in basic
solution.
• Soru: antiasit ilaç tabletlerinin anabileşeni CaCO3 tür. 0.542 gr
olarak tartılan bir tablet HCl ile titre edildiğinde, reaksiyonun
tamamlanması için 38.5 ml 0.200M HCl harcandığına göre tablet
içindeki CaCO3 yüzdesi nedir?
CaCO3
+ HCl → Ca2+ + CO2 + Cl- + H2O
• Konsantrasyou bilinmeyen bir permanganat çözeltisinin 28,97ml si
0,1058g okzalik asit ile tamamen reaksiyona girdiğine göre
permanganat çözeltisinin konsantrasyonunu hesaplayınız.
• MnO4- + H2C2O4 → Mn2+ + CO2
2 MnO4- + 5 H2C2O4 6 H+→ 2 Mn2+ + 10 CO2 + 8H2O
A 25.0 mL sample of vinegar (dilute acetic acid, ) is titrated and
found to react with 94.7 mL of 0.200 M NaOH. What is the molarity
of the acetic acid solution?