1.In general, which type of compounds have the highest melting points (covalent

Question

1.In general, which type of compounds have the highest melting points (covalent compounds or ionic compounds)? (4 points)

2.Based on the structural and chemical characteristics of the crystallized chemicals, which compounds did you expect to be more soluble in water? Explain your reasoning. These are the compounds used in the experiment :Sucrose, sodium chloride, stearic acid, corn starch, sodium bicarbonate (4 points)

3.Were any of the five samples not soluble in water? Did this agree with your expectation/response in question (Sucrose, sodium chloride, stearic acid, corn starch, and sodium bicarbonate( (3.5 points)

4. Were any of the five samples not soluble in ethanol? Did this agree with your expectation/response in question 4? (samples used sucrose, sodium chloride, stearic acid, corn starch and sodium bicarbonate. ((3.5 points)

Thank you !

Explanation / Answer

1) Ionic compounds have higher melting and boiling points than covalent compounds. The electrostatic attraction in an ionic bond is very strong hence a lot of heat energy is required to break it down ,ionic bonds have high melting and boiling points.
However,In covalent bonds, the intermolecular forces are very weak and is easily broken,hence lesser heat is required and thus covalent bonds have lower melting and boiling points.

2) sodium chloride is more soluble in water.

NaCl, or sodium chloride, is an ionic compound with strong positive and negative charges. Water molecules have covalent bonds, but their individual atoms also have charges, and so water is called a polar substance.

When sodium chloride is dissolved in water, the compound breaks apart into individual sodium and chlorine ions. The water molecules are then attracted to these ions' charges, and "hide" them by gathering around them. This is why a salt water solution is colorless.

3)

corn starch does not dissolve in water ,and its simple to prove. Just put some corn starch in water and mix well. Let it sit for 15-20 minutes and you will see all the starch settles to the bottom.

4)

Sugar (or Sucrose) molecules are polar. They have a slight positive end and a slightly negative end. Water molecules have the same property. For this reason, the positive end of a sucrose molecule will be attracted to the negative end of a water molecule and dissolve.

Alcohols are non-polar and are equally charged on all sides. The charged ends of the sucrose have nothing to be attracted to except other SUCROSE molecules, therefore they will not dissolve.

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