Properties of Solution PDF

Properties of Solution Prepared by: DARYL D. VALDEZ, MST  Nature of Solutions ▪ Solutions are homogenous mixtures. ▪ They have uniform composition all throughout. – Ex. Salt and water solution ▪ Solution is composed of solute and solvent.  Terms to remember ▪ Solute-a substance in which the...

Properties of Solution Prepared by: DARYL D. VALDEZ, MST  Nature of Solutions ▪ Solutions are homogenous mixtures. ▪ They have uniform composition all throughout. – Ex. Salt and water solution ▪ Solution is composed of solute and solvent.  Terms to remember ▪ Solute-a substance in which the solute dissolves. ▪ Solvent- a substance that dissolves a solute. ▪ Soluble- a substance that dissolves in another substance is said to be soluble. ▪ Miscible- liquids which are completely soluble in each other are said to be miscible. ▪ Aqueous solution -a solution in which the solvent is water. Types of Solution Type of solution Example solvent Solute GAS Gas in Gas Air Nitrogen (Gas) Oxygen (Gas) LIQUID Gas in liquid Carbonated water Water (liquid) Carbon dioxide (gas) Gas in liquid Ocean water Water (liquid) Oxygen Gas (gas) Liquid in liquid Antifreeze Water (liquid) Ethylene glycol (liquid) Liquid in liquid Vinegar Water (liquid) Acetic acid (liquid) SOLID Liquid in solid Dental Amalgam Silver (solid) Mercury (liquid) Solid in solid Steel Iron (solid) Carbon (solid) The Formation of Solutions How solute dissolves in solvent like water? ▪ Solvation-is the interaction of solvent with the dissolved solute which leads to stabilization of the solute species in the solution. It occurs differently in: – Ionic Compounds in Water – Non Ionic Compounds in Water  Ionic Compounds in Aqueous Solution ▪ Dissolution- the act or process of dissolving into parts or elements. ▪ Solvation- When solvent particles surround the solute particles. Covalent polar Molecules in Aqueous Solution ▪ “Like dissolves like” - meaning a polar molecule will only dissolve a polar molecule, and non-polar dissolves non-polar molecule. How about Non-polar molecules? Concentration of Solution  Concentration Concentration is simply the amount of solute that is present in a given quantity of the solution. A Diluted solution if it contains a greater amount of solvent compared to the solute. A concentrated solution is a solution that contains greater amount of solute compared to the solvent. Solubility ▪ Maximum amount of solute that will dissolve or dissociate in a given amount of solution at specific temperature and pressure. Supersaturated Solution ▪ Supersaturated solution- the maximum amount of solute present in a given amount of solvent at an elevated temperature. Solubility of some Substances with 100grams of water to form saturated solution at specific temperature Concentration of solution Unsaturated Saturated Supersaturated The minimum The maximum The maximum Definition amount of solute amount of solute amount of solute present in a given that can dissolve in a present in a given amount of solvent at given amount of amount of solvent at room temperature solvent at room an elevated temperature. temperature. It is very unstable When solute is When solute is The solute Description added the solute added, the solute no crystallizes when the dissolves longer dissolves solution is cool down. Concentration vs. Solubility ▪ Solubility of a substance in a given solvent is the amount of that substance which is present in a specified quantity (usually 1 litre) of saturated solution at a given temperature. For example, the solubility of sodium chloride in water is 36 grams per 100 grams of the solution at 20 degree Celcius. This means that if you take 100 grams of the salt solution and evaporate off all the water, you will get 36 grams of sodium chloride. Concentration vs. Solubility ▪ Concentration is simply the amount of solute that is present in a given quantity of the solution. ▪ For example, you can think of various salt solutions having different amounts of salt in it. ▪ (1) A solution having 1.5 grams of NaCl in 100 grams of solution OR ▪ (2) A solution having 5 grams of NaCl in 100 grams of solution OR ▪ (3) A solution having 36 grams of NaCl in 100 grams of solution etc. Concentration vs. Solubility Solubility is the maximum amount of the solute that can be dissolved in a given amount of the solvent at specific temperature. While Concentration is amount of solute(which is usually less than maximum amount of solute that can be dissolved in solvent) dissolved in a unit quantity (mass or volume ) of a solution. Solubility of some Substances Quantitative Measures of Concentration of Solution ▪ Concentration of solution - Refers to the relative amount of solute dissolved in a given amount of solution. ▪ There are many ways of expressing the quantity of solute present in a given amount of solvent. –Percent by Mass and percent by volume –Mole Fraction –Molarity –Molality Percent by Mass and Volume 5% acidity 5 grams of acetic acid (solute) dissolve in 95 grams water to make 100 grams of vinegar solution Percent by Mass and Volume 70% solution 70 mL of Isopropyl alcohol diluted with 30 mL purified water by volume  Percent by Mass and Volume ▪ The concentration of Gold Jewellery is expressed in Carat. ▪ 24K Gold is 100% pure Gold with no other metals. ▪ 18K Gold is 75 % gold and 25 % other metals, often copper. Percent by Mass 30 grams sugar ▪ This expresses the mass of solute per 100g 30% of solution. Mass of solution is equal to the mass of solute plus the mass of solvent. 100 grams solution ▪ Ex. In 100g solution of water and sugar, if there are 30 In 100% solution, grams of sugar, there will be 7ograms of water. The formula 30% is solute for percent by mass is: Percent by Volume ▪ If a solution involves a solute and a solvent that are both liquids, then percent by volume is used instead of by mass.  Sample Problem: Percent by Mass What is the percent by mass of a solute with 45.0 g of HCl in 200.0 g solution. Given: Mass solute 45.0 g HCl Mass of solution 200.0g Required: Percent by Mass ▪ Meaning 22.5% of the solution is the solute HCl.  Sample Problem: Percent by Mass What is the percent by Mass and ppm of the following solutions: 1. 30g of NaCl and 105g of water. Given: Mass of solute 30.0g NaCl Mass of solution 30 g NaCl + 105 g water = 135 grams Required: Percent by Mass and ppm  Sample Problem: Percent by Mass How many grams of Sodium Chloride are present in 250g Salt Solution containing 9% sodium chloride Given: 250mL (salt solution) 9% of percent concentration of NaCl or in 100g of solution 9g of it is NaCl Required: Mass of solute  Sample Problem: Percent by Volume A 300 mL sample of wine was found to contain 37.5mL ethanol. What is the percentage by volume concentration of ethanol in the wine bottle? Given: Volume of solute- 37.5mL Volume of solution-300mL Required: Percent by volume  Sample Problem: Percent by Volume A bottle of Hydrogen Peroxide is labelled as 3% by volume. How many mL of Hydrogen Peroxide are in 500mL bottle of this solution? Given: 500mL solution 3% percent concentration H2O2 Required: Volume of Solute Molarity ▪ Molarity (M) is the most common way of expressing the concentration of a solution. ▪ It is defined as the ratio of the number of moles of solute per Liter of Solution. ▪ A 3M (3 molar) of NaOH and water solution means that there are three moles NaOH in one liter of solution or 3 moles NaOH/Liter solution. What is a mole again? ▪ 1 mole of a substance is equivalent to 6.02 x 1023 also known as Avogrado’s number.  Molarity It is defined as the ratio of the number of moles of solute per Liter of Solution. Molarity is important to figure out whether a solution is dilute or concentrated. Sample Problem Since the volume is expressed in mL it Calculate the Molarity should be converted to Liter because, of the solution with 0.2 molarity measures moles/Liter. moles NaOH in 100mL solution. The given number of moles is divided by the given volume of 100 mL and then converted to Liter. Sample Problem Calculate the Molarity of the solution with 5.0g CaCl2 in 250mL solution.  Molar Mass ▪ The mass of one mole of a substance. B. Identify the molar mass of H2O. H- 2(1.00)g it means in 1 mole of H2O O- 1(16.00)g the mass is 18.00 g 18.00 g/mole Get the molar mass of the following CaCl2 - 40𝑔 + 2 35𝑔 = 110𝑔 meaning 1 mole of CaCl2 is 110g 4FeS2 4 55.85 + 2(32.05) = 479.8𝑔/𝑚𝑜𝑙 (NH2)2CO 2 14 + 2(1) + 12 + 16 = 60 𝑔/𝑚𝑜𝑙 Sample Problem Calculate the Molarity of the solution with 5.0g CaCl2 in 250mL solution. Sample Problem Calculate the number of moles of solute in each 100mL of 0.5M H2SO4. Given: Molarity=0.5M or 0.5mol/L Liter of Solution=100mL Molality ▪ Molality (m) of a solution is defined as the number of moles of solute per kilogram of solvent. ▪ It can also be mathematically expressed as ▪ A 3m solution also means 3 moles solute/kilogram solvent. ▪ Although molarity and molality are quite similar, notice that molarity is defined in terms of the volume of a solution, whereas molality is defined in terms of the mass of a solvent only.  What’s the point of Molality? Concentrations expressed in molality are used when studying properties of solutions related to vapor pressure and temperature changes. Molality is used because its value does not change with changes in temperature Sample Problem Calculate the molality of the solution with 0.5 moles of H3PO4 (molar mass=106g) in 250g of water.  Difference of Molarity and Molality Molarity- It is defined as the ▪ Molality (m) of a solution is ratio of the number of moles of defined as the number of moles solute per Liter of Solution. of solute per kilogram of solvent. Mole Fraction ▪ Mole Fraction (X) is the ratio of the number of moles of one component 𝑛𝑎 to the total number of moles in the solution (𝑛𝑎 + 𝑛𝑏 ).  Sample Problem: Mole Fraction A solution is made by dissolving 25 g NaSO4 in 65.0 g H2O. Calculate the mole fraction of the solute and the solvent. Given: Amount of solute: 25g NaSO4 Amount of solvent: 65gH2O END