Study guides. Science 20 cards. Who is known as the first African American scientist. What is Luis Alvarez's cultural background. What was Benjamin Banneker's ethnic background. Which scientist used mathematical knowledge to calculate the exact measurement of the meter. Genetics 20 cards. What are chromosomes made of. How are mitosis and meiosis similar.
What is a gel electrophoresis chamber. In pea plants what are the two alleles for color. Physics 20 cards. Which term explains whether an object's velocity has increased or decreased over time. Which of these is a characteristic of nonmetals.
What is the only factor needed to calculate change in velocity due to acceleration of gravity 9. What term is used to describe splitting a large atomic nucleus into two smaller ones. Q: Why does table salt NaCl dissolve readily in water? Write your answer Related questions. Why does table salt NaCl dissolve readily in water? Does nacl dissolve in water? Why does NaCl readily dissolve in water? Why does nacl readily dissolve in water but not in tetrachloromethane? Is salt soluble in alcohol?
What is the nature of the substances dissolved in water? Give each student an activity sheet. Question to Investigate How does salt dissolve in water? Materials Activity sheet with sodium and chloride ions and water molecules Construction paper, any color Scissors Tape or glue Procedure Make a model of a salt crystal Cut out the ions and water molecules. Arrange the ions on a piece of construction paper to represent a 2-D salt crystal.
Do not tape these pieces down yet. Project an image and have students model what happens when salt dissolves in water. Show students a series of four pictures to help explain the process of water dissolving salt. Model how water dissolves salt Look at the pictures showing how water molecules dissolve salt. Move the water molecules and sodium and chloride ions to model how water dissolves salt. Tape the molecules and ions to the paper to represent water dissolving salt.
Explore Have students conduct an experiment to find out whether water or isopropyl alcohol would be better at dissolving salt. Ask students to make a prediction: Think about the polarity of water molecules and alcohol molecules. Do you think alcohol would be just as good, better, or worse than water at dissolving salt? Be sure students identify variables such as: Amount of water and alcohol used Amount of salt added to each liquid Temperature of each liquid Amount of stirring Question to Investigate Is alcohol just as good, better, or worse than water at dissolving salt?
Place 15 mL of water and alcohol into separate cups. At the same time, add the water and alcohol to the samples of salt. Swirl both cups the same way for about 20 seconds and check for the amount of salt dissolved. Swirl for another 20 seconds and check. Swirl for the last 20 seconds and check.
Carefully pour off the water and alcohol from the cups and compare the amount of undissolved salt left in each cup. Expected Results There will be less undissolved salt in the cup with the water than the alcohol. Explain Discuss how differences in the polarity of alcohol and water explain why water dissolves salt better than alcohol. Ask students: Is alcohol just as good, better, or worse than water at dissolving salt? Alcohol does not dissolve salt as well as water does. How do you know?
There was more salt left behind in the cup with the alcohol. Think about the polarity of water and alcohol to explain why water dissolves more salt than alcohol. Have students look at the models of water and alcohol molecules on their activity sheet. That would be true if all we considered was the energy required to break the ionic interactions, as indicated by the fact that NaCl melts at oC and boils at oC.
But we know that substances like NaCl dissolve readily in water, so clearly there is something else going on. The trick is to consider the whole system when NaCl dissolves, just like we did for molecular species. We need to consider the interactions that are broken and those that are formed. The positive ends of water molecules the hydrogens interact with the chloride ions, while the negative end of the water molecules the oxygen interacts with the sodium ions.
So the ion on the surface of the solid interacts with water molecules from the solution; these water VisChem animation from molecules form a dynamic cluster around the ion. Log In. What scientific concept do you need to know in order to solve this problem? Our tutors have indicated that to solve this problem you will need to apply the Solutions, Molarity and Intermolecular Forces concept.
You can view video lessons to learn Solutions, Molarity and Intermolecular Forces. Or if you need more Solutions, Molarity and Intermolecular Forces practice, you can also practice Solutions, Molarity and Intermolecular Forces practice problems.
If you forgot your password, you can reset it. Join thousands of students and gain free access to 46 hours of Chemistry videos that follow the topics your textbook covers. Analytical Chemistry Video Lessons.
0コメント