# SOLUTIONS A homogeneous mixture in which the components are uniformly intermingled.

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SOLUTIONS A homogeneous mixture in which the components are uniformly intermingled

Terms Solvent – The substance present in the largest amount in a solution. The substance that does the dissolving. Solute – The other substance or substances in a solution. The substance that is dissolved.

ELECTROLYTES Substances that break up in water to produce ions. These ions can conduct electric current Examples: Acids, Bases and Salts (ionic compounds)

SOLUBILITY “Like dissolves Like” – Polar molecules dissolve polar molecules – Nonpolar molecules dissolve nonpolar molecules

SOLUBILITY RULES All common salts of Group I elements and ammonium are soluble All common acetates and nitrates are soluble All binary compounds of Group 7 with metals are soluble except those of silver, mercury I and lead All sulfates are soluble except those of barium, strontium, calcium, silver, mercury I and lead Except for those in Rule 1, carbonates, hydroxides, oxides, sulfides and phosphates are insoluble

Terms Saturated – When a solution contains the maximum amount of solute Unsaturated – When a solvent can dissolve more solute Supersaturated – When the solution contains more solute than a saturated solution will hold at that temperature Concentrated – When a relatively large amount of solute is dissolved Dilute – When a relatively small amount of solute is dissolved

Factors Affecting the Rate of Dissolution Surface Area Stirring Temperature

Temperature vs Solubility

MOLARITY Molarity-the number of moles of solute per liters of solution M = molarity = moles of solute liter of solution

Calculate the molarity of a solution prepared by dissolving 11.5 g of NaOH in enough water to make a 1.50 L solution.

Calculate the molarity of a solution prepared by dissolving 1.56 g of HCl into enough water to make 26.8 ml of solution.

Calculate the number of grams of sodium phosphate required to make 150. ml of a 2.5M solution.

How many liters of solution are needed to dissolve 5.0 g of hydrochloric acid to make a 3.0 M hydrochloric acid solution?

What is the concentration of each ion in a 0.50 M solution of Co(NO 3 ) 2 ? What is the concentration of each ion in a 0.25 M solution of aluminum sulfate?

How many moles of Ag + ions are present in 25.0 ml of a 0.75 M AgNO 3 solution? Calculate the number of moles of Cl - ions in 1.75 L of 1.0 x 10 -3 M AlCl 3

To analyze the alcohol content of a certain wine, a chemist needs 1.00 L of an aqueous 0.200 M K 2 Cr 2 O 7 (molar mass is 294.2g/mol) How much K 2 Cr 2 O 7 must be weighed out to make this solution?

DILUTIONS M 1 x V 1 = M 2 x V 2 What volume of 16 M sulfuric acid must be used to prepare 1.5 L of a 0.10 M H 2 SO 4 What volume of 12 M HCl must be used to prepare 0.75 L of a 0.25 M HCl?

When barium nitrate and potassium chromate react in aqueous solution, the yellow solid barium chromate is formed. Calculate the mass of barium chromate that forms when 3.50 x 10 -3 mole of solid barium nitrate is dissolved in 265 ml of 0.0100 M potassium chromate solution.

MOLALITY A unit of concentration equal to the number of moles of solute per kilogram of solvent m = moles of solute kg solvent

98.0 g RbBr in 824 g water 85.2 g SnBr 2 in 1.40 x 10 2 g water

Phase Change Diagram

Definition Boiling Point – when the vapor pressure of the liquid is equal to the atmospheric pressure

Freezing Point Depression/ Boiling Point Elevation Colligative property – a solution property that depends on the number of solute particles present (ie – f.p. and b.p.) – Freezing Point Depression – Boiling Point Elevation

Calculating Boiling Points K bp = boiling point constant – Water 0.515 O Ckg/mol – 1 mole of a solute particle will raise the bp of 1 kg of water by 0.515 O C 1m solution of sugar water 1(0.515 O C) 100.515 O C 1m solution of NaCl water 2(0.515 O C) 101.03 O C 1m solution of CaCl 2 water 3(0.515 O C) 101.545 O C

Calculating Freezing Points K fp = freezing point constant – Water 1.853 O Ckg/mol – 1 mole of a solute particle will lower the fp of 1 kg of water by 1.853 O C 1m solution of sugar water 1(1.853 O C) -1.853 O C 1m solution of NaCl water 2(1.853 O C) -3.706 O C 1m solution of CaCl 2 water 3(1.853 O C) -5.559 O C

ΔT fp = im K fp ΔT bp = im K bp K fp = 1.853 o Ckg/molK bp = 0.515 o Ckg/mol If 26.4 grams of nickel II bromide are dissolved in 224 grams of water, what will be the new boiling point and freezing point of the resulting solution?

If 25.0 grams of calcium chloride are dissolved in 500 grams of water, what will be the new boiling point and freezing point of the resulting solution?

MASS PERCENT A unit of concentration equal to the mass of solute per mass of solution partx 100 whole

A solution is prepared by mixing 1.00 g of ethanol with 100.0 g of water. Calculate the mass percent of ethanol in this solution. A 135 g sample of seawater is evaporated to dryness, leaving 4.73 g of salt. Calculate the mass percent of salt in the saltwater.

1.Molarity (M) = 2.Mass (weight) percent = 3.Mole fraction (  A ) = 4.Molality (m) =

Sol’n is prepared by adding 5.84 g of formaldehyde (H 2 CO) to 100.0 g water. Final vol of solution is 104.0 mL. Calculate the molarity, molality, mass % and .

M = 1.87 M H 2 CO m = 1.94 m H 2 CO Mass %= 5.52 % H 2 CO  =.0338

Molecular Mass Determination If 99.0 g of a nonionizing solute dissolved in 669 grams of water and the freezing point of the resulting solution is -0.960 o C, what is the molecular mass of the solute? ΔT fp = im K fp m = ΔT fp K fp

If 64.3 g of a nonionizing solute dissolved in 390. grams of water and the boiling point of the resulting solution is 100.680 o C, what is the molecular mass of the solute? ΔT bp = im K bp m = ΔT bp K bp

Anthraquinone contains only carbon, hydrogen and oxygen and has an empirical formula of C 7 H 4 O. When 15.93g of anthraquinone are added to 1 kg of water the freezing point depression was determined to be 0.240 o C. Calculate the molar mass of the biomolecule (K f for chloroform is 4.70 o Ckg/mol)

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