Quiz 2 practice Quiz

Transcription

1 Name: ate: 1. The following data were recorded while determining the solubility of a certain salt. Temp. ( C) Grams Solute/ 100 g H 2 O Which graph best represents the solubility of this salt?. 2. The solubility of a salt in a given volume of water depends primarily on the. surface area of the salt crystals. temperature of the water C. rate at which the salt and water are stirred. pressure on the surface of the water. 3. solution of NaNO 3 contains 1 gram of solute dissolved in 100 grams of water. ccording to Reference Table, at 50 C this solution is considered C... unsaturated and concentrated. unsaturated and dilute C. saturated and concentrated. saturated and dilute page 1

2 4. ccording to Reference Table, approximately how many grams of KClO 3 are needed to saturate 100 grams of H 2 O at 40 C? 6. ccording to Reference Table, a temperature change from 60 C to 90 C has the least effect on the solubility of C SO 2. NH 3 C. KCl. KClO 3 5. solution containing 60 grams of NaNO 3 completely dissolved in 50 grams of water at 50 C is classified as being. saturated. supersaturated C. dilute and unsaturated. dilute and saturated 7. Which procedure will increase the solubility of KCl in water?. stirring the solute and solvent mixture. increasing the surface area of the solute C. raising the temperature of the solvent. increasing the pressure on the surface of the solvent page 2

3 8. If the solubility of NaCl at 25 C is 36.2 g/100 g H 2 O, what mass of NaCl can be dissolved in 50.0 g of H 2 O? g g C g g 10. Many laboratory preparations of solutions call for stirring the solvent while adding the solute. Which of the following is always an effect of this procedure?. It decreases the reactivity of the solute.. It decreases the solubility of the solute. C. It brings the solute and solvent rapidly into contact.. It produces a double displacement reaction. 9. technician prepared a solution by heating 100 milliliters of distilled water while adding KCl crystals until no more KCl would dissolve. She then capped the clear solution and set it aside on the lab bench. fter several hours she noticed the solution had become cloudy and some solid had settled to the bottom of the flask. Which statement best describes what happened? 11. Three 10 g samples of sugar are represented below.. s the solution cooled, evaporation of water increased the KCl concentration beyond its solubility.. Water molecules, trapped with the KCl crystals, were released after heating. C. t lower temperatures the solubility of the KCl decreased and recrystallization occurred.. t increased temperatures the solubility of KCl increased and remained too high after cooling. Sample dissolves in water more slowly than sample. Sample dissolves more slowly than sample C. Which of the following best explains why sample dissolves most slowly?. It has the most volume.. It has the smallest surface area. C. It has the largest number of sugar molecules.. It has the fewest bonds between sugar molecules. page 3

4 12. solution that contains less solute than it can hold at a given temperature is 15. The diagram below shows a cube of sodium chloride beginning to dissolve in water.. disassociated.. saturated. C. supersaturated.. unsaturated. 13. Which of the following samples of sugar will dissolve fastest in a pitcher of lemonade?. 5 g of cubed sugar in 5 C lemonade. 5 g of cubed sugar in 20 C lemonade C. 5 g of granulated sugar in 5 C lemonade. 5 g of granulated sugar in 20 C lemonade Which of the following changes will cause the cube to dissolve more quickly?. swirling the flask. removing the stopper C. pouring off half the water. decreasing the water temperature 14. student made a homogeneous mixture of water and salt. Which of the following statements applies to this homogeneous mixture?. This mixture is a solution.. This mixture is a pure substance. C. The salt is not evenly distributed throughout this mixture.. The salt chemically combines with the water in this mixture. page 4

5 This graph shows the solubility curves for various ionic compounds. Which solute exhibits the least response to temperature change?. NH 4 Cl. KCl C. HCl. NH 3 Which compound is most affected by a change in temperature from 30 C to 50 C?. CsNO 3. NH 4 r C. CuSO 4. KCl page 5

6 18. The following graph shows solubilities of various salts in 100. grams of water at temperatures ranging from 0 C to 100 C. Use the graph to answer the following question(s). 20. Using the solubility graph provided, a student performs an experiment to find the solubility of a substance. The student finds the amount of substance needed to make a saturated solution in 100 g of water at different temperatures. The student s data are shown in the table below the graph. What mass of KCl is necessary to form a saturated solution if the KCl is dissolved in 200. g of water at 50.0 C? g g C g g 19. If water is allowed to evaporate from an unsaturated saltwater solution, how will the concentration of the solution change?. The concentration will decrease. Student ata Trial Temperature ( C) Salt in 100 g of water (g) of Water What is the identity of the substance?. Sodium Nitrate. Potassium Nitrate C. Sodium Chloride. Potassium Chlorate. The concentration will first increase, then decrease. C. The concentration will remain the same.. The concentration will increase. page 6

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