Presentation on theme: "A chemical reaction is a process one or more substances are transformed into another substances. Physical change - color change - solid formation (precipitation)"— Presentation transcript:
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 equationis an expression of a chemical reaction by using symbols and formulas. reactants In a reaction the starting substances are called 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. CH 4 + O 2 CO 2 + H 2 O Stoichiometric coefficients are the numbers placed in front of formulas in a chemical equation. The balanced reaction is, CH 4 + 2 O 2 CO 2 + 2 H 2 O. Left side containsRight side contains 1 C 4 H2 H 2 O3 O
2 H 2 (g) + O 2 (g) 2 H 2 O (s) 2 molecules H 2 1molecules O 2 2 molecules H 2 O two moles of H 2 reacts with one mole O 2 and two moles H 2 O is produced. 4 grams of H 2 reacts with 32 g O 2 and 36 g H 2 O is produced.
how many moles and grams of H 2 O are produced by burning 2.72 moles H 2 a) in an excess of O 2 b) with 1 mol O 2
Ballance the following reactions N 2 H 4 + N 2 O 4 N 2 + H 2 O NaOH + CO 2 Na 2 CO 3 + H 2 O CaO + P 4 O 10 Ca 3 (PO 4 ) 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 I 2 mixed? Sb + I 2 SbI 3 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 AgNO 3 ? KBr + AgNO 3 AgBr + K + + NO 3 -
Consider the following reaction: Na 3 PO 4 (aq) + Ba(NO 3 ) 2 (aq) Ba 3 (PO 4 ) 2 (s) + NaNO 3 (aq) Suppose that a solution containing 3.50 grams of Na 3 PO 4 is mixed with a solution containing 6.40 grams of Ba(NO 3 ) 2. How many grams of Ba 3 (PO 4 ) 2 can be formed?
Yields of chemical reactions theoretical yield. 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. actual yield. The amount of product actually obtained is called the actual yield. The percent yields The percent yields is the ratio actual yield to the theoretical yield times 100%
Soru: Fe + O 2 Fe 2 O 3 Reaksiyonunda 11.2g Fe yeteri kadar oksijenle reaksiyona girdiğinde 10.0g Fe 2 O 3 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?
Na 3 PO 4 (aq) + Ba(NO 3 ) 2 (aq) Ba 3 (PO 4 ) 2 (k) + NaNO 3 (aq) When 3.50 Na 3 PO 4 reacts ewith 6.40 gram Ba(NO 3 ) 2 how many grams of Ba 3 (PO 4 ) 2 will produce?
Soru: 3,00g etilenamin CH 3 NH 2, 0,100g H + ile reaksiyona girdiğinde 2,60g CH 3 NH 3 + oluştuğuna göre reaksiyonun gerçek verimi ve yüzde verimini hesaplayınız. CH 3 NH 2, + H + → CH 3 NH 3 CH 3 NH 2, : 31,06 CH 3 NH 3 :32,07
Reactions in Aqueous Solution Precipitation Reactions Acids, Bases, and Neutralization Reactions Oxidation–Reduction (Redox) Reactions
Çözelti: Homogeneous mixtures are called solutions solventsolute 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 = --------- M A Molarity n M= ------- mol/L V density m d = ---------- gr/mL V
Diluting Concentrated Solutions M initial x V initial = mol number = M final x V final M initial x V initial = M final x V final
Find the molarity of a solution that 23.4g of Na 2 SO 4 was dissolved in water and diluted to 250.0ml Na 2 SO 4 : 142 calculate the molarity of H 2 SO 4 solution when we dilute 50.0 mL of a solution of 2.00 M H 2 SO 4 to a volume of 200.0 mL.
Q1 How can you prepare 500ml 0.10 M H 2 SO 4 solution from 3.0M H 2 SO 4 ? Q2 How would you prepare 500.0 mL of 0.2500 M NaOH solution starting from a concentration of 1.000 M? Q3 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?
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 NH 4 + are soluble all nitrates, acetates and perchlorates are soluble NO 3 (Nitrat), CHCOO - (asetat),ClO 4 (perklorat) all chlorides (halogens) are soluble except (AgCl, Hg 2 Cl 2, PbCl 2 ) most sulfates ( SO 4 2+ ) are soluble except (Sr SO 4, Ca SO 4, Ba SO 4, Pb SO 4 ) Cl-, Br-, I- SO 4 2 - Li+, Na+, K+, Rb+, Cs+ NH 4 + NO 3 - ClO 4 - CH 3 CO 2 -
solubility rules Slightly soluble all OH- hydroxides are insoluble except those of 1A group (Na, K, Li,) and NH 4 + all sulfides S 2- are insoluble except those of 1A group (Na, K, Li,) and NH 4 + all carbonates are insoluble except those of 1A group (Na, K, Li,) and NH 4 + All PO 4 3- are insoluble except those of 1A group (Na, K, Li,) and NH 4 + CO 3 2-, PO 4 3- OH -, S 2-
Acids and Bases AsitBaz Have a sour taste, dissolve metals such as zinc and carbonate minerals change color of litmus to red -Have a bitter taste, -Have a slippery feel -change color of litmus to blue, -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 acid and the OH - ion from the base to form water, H 2 O H + (aq) + OH - (aq) H 2 O (l)
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 + H 2 O Cl – + H 3 O + A base is a species having tendency to accept an H + ion. NH 3 + H 2 O NH 4 + + OH - In 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 AsitZayıf 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 - CH 3 COOH +H 2 O CH 3 COO - + H 3 O + HCl, HBr, ve HI HNO 3, H 2 SO 4, HClO 4 gibi Oksiasitler HF. HCN, H 2 S HClO, HNO2, ve H3PO4 Organik asitler (RCOOH), CH 3 COOH C 6 H 5 COOH
Asit ve bazların Kuvvetliliği Kuvvetli bazZayıf 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 - NH 3 +H 2 0 NH 4 + + OH - M 2 O 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 (:NH 3 ) 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 Fe 2 O 3 (k) + 3 CO(g) → 2 Fe(k) + 3 CO 2 (g) Fe 3+ --- metallic iron CO(g)---- Carbon diokside
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: Fe 2+ + MnO 4 - → Fe 3+ + Mn 2+ balance in acidic medium Soru: Cl 2 + Cr(OH) 3 → Cl- + CrO 4 2- balance in basic medium Soru: C 2 H 5 OH + Ce 4+ → CO 2 + Ce 3+ 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 CaCO 3 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 CaCO 3 yüzdesi nedir? CaCO 3 + HCl → Ca 2+ + CO 2 + Cl - + H 2 O
Konsantrasyou bilinmeyen bir permanganat çözeltisinin 28,97ml si 0,1058g okzalik asit ile tamamen reaksiyona girdiğine göre permanganat çözeltisinin konsantrasyonunu hesaplayınız. MnO 4 - + H 2 C 2 O 4 → Mn 2+ + CO 2 2 MnO 4 - + 5 H 2 C 2 O 4 6 H + → 2 Mn 2+ + 10 CO 2 + 8H 2 O
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?