Could you please give me a discriptive answer and explain what each term means? I have a hard time understanding chemistry. Thanx
q1
In a reaction between aqueous solutions of calcium chloride and sodium carbonate, a precipitate is formed. The experimental procedure which can be used to separate the solid from the solution is
A. titration
B. filtration
C. gas collection
D crystalization
q2.
Which technical procedure is similiar to the natural process which forms salt seposits?
A. titration
B. filtration
C. crystalization
D. fractional distillation
q3.
To determine the concentration of salt in ground water, the salt can be separated from the solution by
A. fractional distilling
B. filtering the solution
C. evaporating the solvent
D. lowering the temperture of the solution
Could you please give me a discriptive answer and explain what each term means? I have a hard time understanding chemistry. Thanx
q1
In a reaction between aqueous solutions of calcium chloride and sodium carbonate, a precipitate is formed. The experimental procedure which can be used to separate the solid from the solution is
A. titration
B. filtration
C. gas collection
D crystalization
Titration is when you have a known standard (such as 0.20 M HCl) and you use that, usually with an indicator, to determine the concentration of unknown solution. Usually a buret is used to add the titrant.
Filtration is a method to separate a solid phase from a liquid phase. For example, in the above example, CaCO3 is the precipitate (the solid) and you want to separate it from the liquid. The usual set up is to fold a piece of filter paper into fourths, place the folder paper into a 60 degree funnel, and pour the liquid and solid through. Gravity is what runs the system. It often takes quite some time, especially if the filter paper is not very porous. I don't know if you have been introduced to Buchner funnels or not but they are frequently used in organic chemistry to separate solids and liquids. They are much much larger than the small glass 60 degree funnels (often as much as 3-4 inches in diameter). A piece of filter paper is placed in the funnel (it has fairly large holes in the bottom (1/16 or 1/8 inch), the funnel is inserted into a flask, and the flask is connected to a water aspiration system so that a vacuum is pulled on the flask. That pulls the solvent through, usually quite quickly.
Gas collection usually entails allowing gas from a generator to flow into an inverted bottle of water. The gas displaces the water. You may remember collecting oxygen this way, or hydrogen gas, in freshman chemistry.
Crystallization is a way of purifying products that are made in some chemical reactions. It involves taking the product, a solid, and dissolving it in the minimum amount of some solvent at an elevated atemperature. Then the solution is allowed to cool and the solid will recrystallize in purer form if the right solvent was chosen.
q2.
Which technical procedure is similiar to the natural process which forms salt seposits?
A. titration
B. filtration
C. crystalization
D. fractional distillation
I have defined A, B, and C above. D of this part, fractional distillation, is performed by placing a mixture of liquids to be separated in a flask that can be heated. There is a side arm on the top part of the neck of the flask and a condenser is connected to the side arm. Finally, a thermometer is placed in the top of the flask (both to seal it off AND to allow us to know the temperature of the vapors). In practice, the flask is heated, vapors rise to the top, go through the open side arm, are condensed back to a liquid in the condenser, then drip out the bottom into a flask, beaker, or other container. The thermometer tells us the temperature at which that first product distilled. The temperature will stay at that point until all of "substance A" is distilled, then the temperature will rise until the next component vaporizes and goes through the same process. The mixture of liquids in the boiling pot is separated in this fashion into its "fractions" which is why it is called fractional distillation.
q3.
To determine the concentration of salt in ground water, the salt can be separated from the solution by
A. fractional distilling
B. filtering the solution
C. evaporating the solvent
D. lowering the temperture of the solution
I have defined A and B above.
C. evaporatiing the solvent is simple. We have a solution consisting of a solute (often a solid) dissolved in a solvent (usually a liquid). We let the solvent evaporate (just like water evaporates from a spill on the floor if we don't mop it up) and the solid is left behind in crystals.
D. Solutes are USUALLY more soluble in a solvent at elevated temperatures; therefore, lowering the temperature will often cause a solute to crystallize. This process actually is just a part of what was described in crystallization above.
I haven't given you the answers to any of these but just answered your question by giving definitions. Repost if there is something you don't understand.
q1. In a reaction between aqueous solutions of calcium chloride and sodium carbonate, a precipitate is formed. The experimental procedure which can be used to separate the solid from the solution is:
A. titration: Titration is a method used to determine the concentration of an unknown solution by reacting it with a known standard solution. It involves adding a solution of known concentration to the unknown solution until a chemical reaction indicates that the desired endpoint has been reached.
B. filtration: Filtration is a method used to separate a solid from a liquid by passing the mixture through a filter. The solid particles get trapped on the filter paper, while the liquid passes through, resulting in the separation of the solid from the solution.
C. gas collection: Gas collection involves collecting gases generated in a reaction by displacing a liquid, usually water, in an inverted bottle. The gas displaces the liquid and collects in the bottle, allowing it to be studied or further processed.
D. crystallization: Crystallization is a process used to purify solid compounds that involves dissolving the compound in a solvent, then allowing the solution to cool or evaporate slowly. As the temperature drops, the solute molecules come together and form ordered crystal structures, separating from the solution.
q2. Which technical procedure is similar to the natural process that forms salt deposits?
A. titration: Titration is not similar to the natural process of salt formation.
B. filtration: Filtration is not similar to the natural process of salt formation.
C. crystallization: Crystallization is similar to the natural process of salt formation. In nature, salt deposits, such as those found in salt mines or evaporated salt lakes, form through the slow evaporation or cooling of saltwater. The dissolved salt crystallizes out of the solution and forms salt crystals.
D. fractional distillation: Fractional distillation is not similar to the natural process of salt formation.
q3. To determine the concentration of salt in groundwater, the salt can be separated from the solution by:
A. fractional distillation: Fractional distillation is not a suitable method to separate salt from groundwater.
B. filtering the solution: Filtering the solution can remove solid impurities, but it may not separate the salt from the water entirely.
C. evaporating the solvent: Evaporating the solvent is a method to separate salt from the solution. By heating the solution and allowing the water to evaporate, the salt will be left behind as crystals.
D. lowering the temperature of the solution: Lowering the temperature of the solution can cause the salt to crystallize out of the solution. This process is similar to crystallization, where the solute becomes less soluble as temperature decreases, leading to the formation of salt crystals.
I hope this explanation helps you better understand the concepts of chemistry and the principles behind the different techniques discussed. If you have any further questions, feel free to ask!