Core Concept: Mixtures PDF

Core Concept: Mixtures Mixtures are 2 or more pure substances mixed. A mixture can consist of elements, compounds, or mixtures physically combined. Mixtures can be separated into their original parts using physical separation methods. ◦ Homogenous mixtures may be more difficult to separate. ◦ M...

Core Concept: Mixtures Mixtures are 2 or more pure substances mixed. A mixture can consist of elements, compounds, or mixtures physically combined. Mixtures can be separated into their original parts using physical separation methods. ◦ Homogenous mixtures may be more difficult to separate. ◦ Mixtures are not chemically bonded. ◦ Mixtures can contain different states of matter like gaseous CO2 dissolved into liquid H2O. ◦ Compounds and molecules can only be separated chemically, while mixtures can be separated using physical separation techiques.  Core Concept: Mixtures Characterist Homogenous Mixture Heterogeneous Mixture ics A homogenous mixture is the type of The heterogeneous mixture is the mixture in which the composition of type of mixture in which the Definition the solute is uniform throughout the composition of the solute is not mixture. uniform throughout the mixture. Mixtures may be homogenous or The size of the particles dispersed in heterogenous. the mixture usually lies within the The size of the particles dispersed in a heterogeneous mixture is larger. Particle size range of atomic and molecular size.  A homogeneous mixture appear The particles are not visible with the The particles are mostly visible with uniform throughout and do not naked eyes. the naked eyes. experience "settling". The particles are The components of a homogenous The components of a heterogeneous evenly distributed throughout a Differentiation mixture cannot be distinguished mixture can be distinguished as homogenous mixture; any sample within the mixture. separate components. taken would be representative of the The components of a homogenous The components of a heterogeneous whole. mixture cannot be separated by Separation mixture can be separated by simple simple physical means like filtration physical means like filtration. and sieving.  A heterogenous mixture does not All parts of the mixture have the Different parts of the mixture might appear uniform and particles are not Properties same physical and chemical have different physical and chemical perfectly evenly distributed properties. properties. throughout. In addition, the ratio of Colloids and suspensions are Solutions are examples of the components may be variable or not Examples homogenous mixture. examples of a heterogeneous mixture. fixed in a heterogenous mixture. Core Concept: Mixtures Homogenous Mixture Heterogenous Mixture Metal Alloys Blood Sugar water Sand and salt Air Chex mix Lemonade Gravel Soda Chocolate milk  Core Concept: Mixtures Homogenous mixtures that are fluids are called solutions. Solutions have a solute (what is being dissolved and is less than 50% of the particles) and a solvent (what is doing the dissolving and is greater than 50% of the particles). Examples of Solutions  Sugar mixed with water  Air  Salt mixed with water  Vinegar and water **Metal Alloys like steel and brass are homogenous mixtures but are not referred to as solutions.** Core Concept: Electrolytes in Solution Video Resource: Electrolytes in Solution NaCl separates into Na+ and Cl- ions in solution. https://youtu.be/jg2uJFa8EVo Salts, like NaCl, are strong electrolytes and conduct electrical current. Organic carbon-based molecules like sugar are often nonelectrolytes. Core Concept: Water as a Solvent Water is known as the universal solvent. Because water is ubiquitous in our environment (and ourselves!) and has polar bonds and special intermolecular forces, water can dissolve more substances than most solvents. For this reason, it is called the universal solvent. However, not all substances are soluble to a great degree in water. Substances that are not polar will not dissolve well in water. Remember: "Like dissolves like".  Core Concept: Solubility Soluble – if a substance can be dissolved in a solvent Solubility is the degree to which a substance is soluble or is miscible in another substance. Only changes in temperature will affect the solubility for a solid. Solids are more soluble at high temperatures. For gasses, changes in pressure and temperature will affect solubility. Gasses are more soluble at low temperature and high-pressure conditions. Miscible is whether a substance can dissolve (at all) in a solvent. Oil and water are said to be immiscible. Rate of dissolution is how fast a solute dissolved into a solvent. For solids, increasing temperature, increasing agitation, and increasing surface area can all increase the rate of dissolution. Video Resource: Solutions https://youtu.be/XEAiLm2zuvc  Unsaturated Solution is defined as a solution in which more solute Saturatio could still be dissolved at the same temperature/ pressure conditions. Saturated Solution is defined as a solution in which the maximum n of amount of dissolved solute is present in solution at the given temperature/ pressure conditions. Solutions Supersaturated solution is a solution that contains more than the maximum amount of solute that is capable of being dissolved at a given temperature. The recrystallization of the excess dissolved solute in a supersaturated solution can be initiated by the addition of a tiny crystal of solute, called a seed crystal.  How to Make a Supersaturated Solution Making a Supersaturated https://youtu.be/qcpiDBya_Nw Solution Remember these are temporary solutions 1) Dissolve the maximum amount of solute in solvent to create a saturated solution 2) Apply heat to the solution (making an unsaturated solution). Add more solute. 3) Remove solution from the heat. As it cools, the solution forming is a supersaturated solution. 4) A "seed crystal" will begin the process of crystallization  Core Concept: Solubility Curves A solubility curve shows the amount of solute per 100g (or defined amount) of solvent that can dissolve.  The curve line represents a perfectly saturated solution  The area above the curve represents a super saturated solution  The area below the curve represents an unsaturated solution  Core Concept: Solubility Curves Gasses tend to be LESS soluble with an increase in temperature of the system.  NH3 and SO2 are gasses (see the curve) Most solid solutes will increase in solubility as temperature of the system increases; however, differences can be accounted due to different IMF of molecules.  At 80°C about 40g of NaCl forms a saturated solution with 100g of water. For KCl, about 52g at the same temperature forms a saturated solution with 100g of water.