Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Mixt and Sep
Mixtures and Separations
| Question | Answer |
|---|---|
| Pure substance | Matter which is comprised only of one type of material. May be elements or compounds. |
| Mixture | Consists of two or more different substances physically combined. Each component retains its own independent properties and has not undergone any chemical reactions. |
| Homogenous mixture | Mixture of uniform composition. Component parts cannot be distinguished from each other. All solutions fall into this category. Eg. salt dissolved in water, metal alloys etc |
| Heterogenous mixture. | Mixture of non-uniform composition. Component parts can be distinguished from each other. Suspensions and colloids fall into this category. E.g. salt and sand mixture, mayonnaise, muddy water etc. |
| If there is only one kind of atom, it is an | element |
| If there are two or more kinds of atoms joined together in the same ratio | it is a compound |
| If there is a combination of two or more elements and or compounds then it is a | mixture |
| What is a molecule? | Two or more atoms held together by a covalent bond. |
| What is an atom? | The smallest, indivisible unit of an element which can exist on its own. |
| Solution | A homogenous mixture consisting of two or more components, one of which is usually a liquid. |
| Define solute. | Substance which dissolves. |
| Define solvent. | Substance in which a solute dissolves. |
| Solute + solvent -> | solution |
| What type of solution is sea water? | Solid in liquid solution (NaCl in water) |
| What type of solution is soda water? | Gas in liquid solution (CO2 in water) |
| What type of solution is brass? | Solid in solid solution i.e. metal alloy (Zinc in copper) |
| What type of solution is white rum? | Liquid in liquid solution (Ethanol in water) |
| What type of solution is air? | Gas in gas (O2, H2O, Ar, CO2 in N2) |
| What is a suspension? | A heterogenous mixture in which minute, but visible, particles are disperses in another substance, usually a liquid. Eg. chalk in water, dust in air, muddy water |
| What is a colloid? | A heterogenous mixture in which the particles of one substance are dispersed in another substance, usually a liquid. The dispersed particles are smaller than those of a suspension but larger than those of a solution. E.g. smoke, fog, aerosol sprays, mayo |
| What type of colloid is smoke? | Solid in gas (solid aerosol) (carbon/soot in air) |
| What type of colloid is aerosol spray? | Liquid in gas (liquid aerosol) (e.g. paint in propellant) |
| What type of colloid is mayonnaise? | Liquid in liquid (emulsion) Egg in vinegar/lemon juice |
| What type of colloid is jelly? | Solid in liquid (gel) (sugar/pectin in fruit juice) |
| How can solutions, suspensions and colloids be distinguished in terms of particle size? | Solution - very small (less than1 nm) (not visible to naked eye) Colloid - greater than that of a solution but still not visible to naked eye ( 1 - 1000 nm) Suspension - large, visible to naked eye (greater than 1000 nm) |
| How can solutions, suspensions and colloids be distinguished in terms of type of mixture? | Solution - homogenous Colloid - heterogenous Suspension - heterogenous |
| How can solutions, suspensions and colloid be distinguished in terms of appearance? | Solution - generally transparent Colloid - usually opaque, some are translucent Suspensions - opaque |
| How can solutions, suspensions and colloids be distinguished in terms of ability to separate by filtration? | Solutions - no Colloids - no Suspensions - yes (their components can be separated by filtration) |
| How can solutions, suspensions and colloids be distinguished in terms of ability to separate by settling? | Solution - no Colloid - no Suspension - yes (components can be separated by settling for a while) |
| How can solutions, suspensions and colloids be distinguished in terms of transmission of a beam of light? | Solution - transmits light Colloid - scatters light (Tyndall effect) Suspension - does not transmit light |
| Define solubility. | The mass of solute that will saturate 100 g of solvent at a given temperature. Solubility = (Mass of dissolved solute/Mass of solvent ) x 100 |
| State the unit of solubility. | g per 100 g water |
| What is the effect of temperature on the solubility of a substance? | Solubility increases as temperature increases. |
| What is a saturated solution? | A solution which contains as much solute as can be dissolved at a given temperature, in the presence of undissolved solute. |
| What is a solubility curve? | A graph which shows the solubility of a given solute against temperature. |
| What are two pieces of information which can be obtained from a solubility curve? | 1) The solubility of a solid at any temperature within the range of the graph. 2) The temperature at which crystals would start to form if an unsaturated solution containing a fixed mass of solute is cooled to the point of saturation. |
| T or F. Mixtures can be separated by physical separation techniques since the components are not chemically combined. | T |
| This method is used to separate an insoluble solid from a liquid. Separating principle is based on differences in particle size. | Filtration. |
| This method is used to separate a solid dissolved in a liquid in order to collect the solid. Separating principle is differences in boiling point. | Evaporation and crystallization |
| What is simple distillation used to separate? | Solid dissolved in a liquid usually to collect the liquid. Separating principle is based on difference in boiling points. |
| What is fractional distillation used to separate? | Two or more miscible liquids (liquids which mix completely together forming a homogenous mixture) which have differences in boiling points. |
| What is the separating funnel used to separate? | A mixture of two or more immiscible liquids (they do not mix). Separating principle is based on differences in density. |
| What is chromatography used to separate? | A mixture of dissolved substances which will travel through a material. The components are separated based on their different solubilities in a solvent and attraction to the material. |
| List the sequence of stages involved in the extraction of sucrose from sugarcane. | 1)Shredding 2) Crushing 3) Clarification/Precipitation 4) Filtration 5) Boiling/Vacuum distillation 6) Crystallization 7) Centrifugation 8) Collection |
| What is the purpose of adding calcium hydroxide (Ca(OH)2) (i.e. lime water) to cane juice in the extraction process. | The cane juice which enters the clarifier is acidic. The calcium hydroxide neutralizes any acids present and causes impurities to precipitate out i.e. they are converted to larger, insoluble particles which are removed. |
| Why is vacuum distillation used in the boiling stage? | The boilers are under successively lower pressures so that as the juice passes from one to the next it boils at successively lower temperatures. In this way, the water evaporates and the juice is concentrated but ot charred or caramelized by the process. |
Created by:
CSEC Chemistry 10th Grade
Popular Chemistry sets