Volatility Lab Report

Does the type of bond determine the volatility of a substance? Explain. (3 pts)

Yes, the type of bond does determine the volatility of a substance. Volatility is measure of how much a substance vaporizes into the air. Compound B, (covalent bond) was more volatile, rating a 4 on the volatility scale of 0-4, 4 being the highest and 0 being the lowest. Compound A (ionic) on the other hand, rated a 2. The reason that compound B was more volatile is because ionic bonds consist of a strong positive and a negative charge which prevent them from breaking apart, and vaporizing into. Covalent bonds are weaker because they have to share electrons between multiple atoms, and often just cloud around each other. This means that covalent bonds can be more

easily broken, and vaporize into the air.

Does the type of bond influence the conductivity of a substance. Explain. (3 pts)
Yes, the type of bond does influence the conductivity of a substance. The term conductivity refers to the ability of a material to pass on electricity. Compound A (ionic) rated a 3 on the scale of 0-4 on conductivity, 4 being the highest and 0 being the lowest. Compound B (covalent) rated a 0, meaning that it was not conductive at all. This shows that substances with ionic bonds are more conductive than substances with covalent bonds. I believe that this is because since ionic compounds have stronger the bonds, they have less of a chance to lose electricity between the two atoms. Also, metals are usually more conductive than non-metals and ionic bonds happen between a metal and a non-metal, while covalent bonds happen between two non-metals. Thus, ionic bonds are more conductive.

Water molecules have parts that are negatively charged and parts that are positively charged. Which substances tend to dissolve easier in water, ionic or covalent? Why? (3 pts)
Yes, ionic compounds tend to dissolve easier in water.

The word dissolve means to mix and dissipate into a substance. In our data, compound A (ionic) rated a 3 on the scale of 0-4, 0 being not at all soluble, and 4 being completely dissolved. Compound B (covalent) rated a 0 on the same scale of solubility. This means that ionic compounds are more soluble than covalent compounds. I think that this is because of the positive and negative parts that make up an ionic bond. Since water molecules have both negative and positive parts, the atoms forming the ionic bonds would split up, and bond with other atoms. For example, if the ionic compound Sodium fluoride (Sodium+Fluorine) compound broke apart, Fluorine might bond with a hydrogen atom in the water. This is because Fluorine has 7 valence electrons and has a -1 charge and Hydrogen has 1 valence electron and a +1 charge. The two atoms combined would satisfy an octet (8

electrons).

Does the strength of the bond have anything to do with the melting point of a substance? Explain using examples from research. (Hint: Look back at the melting point research) (3 pts)
Yes, the strength of the bond does affect the melting point of a substance. The melting point of a substance is the temperature it takes to turn that substance into its liquid form. Stronger bonds (ionic) tend to have a much higher melting point than weaker bonds (covalent). For example, in our melting point research, Sodium fluoride (ionic) had a melting point of 993°C. In contrast, Sulfur dioxid (covalent) had a melting point of −72 °C, which was drastically lower than the melting point of Sodium fluoride. Ionic compounds have a strong bonds because they form between a metal and a non-metal, which are held together by a positive and negative charge stuck tightly together. This means that ionic bonds take more energy to break apart, and to turn into liquid. Since covalent bonds are weaker and have to share electrons, they tend to drift apart easier and melt into their liquid state.

Critical Thinking and Application (If you do any research be sure to cite your sources.)

Based on your data, make a case for the unknown to be a covalent or an ionic compound. Be sure to cite data to back up your statements. Also predict its melting point. (3 pts)
I think that the unknown compound is ionic. This is because on our test, it showed many traits of an ionic compound. In all experiments, it had a closer number to the ionic compound. For example, for solubility, the ionic compound (A) rated a 3 on the scale of 0-4, 4 being the most soluble and 0 being not soluble. The covalent compound (B) rated a 0, and the unknown compound (C) rated a 4. On our data table, I have seen this trend, where Compound A and Compound C have very close results, and Compound B is isolated, with different results.
I predict that its melting point will be high since it is an ionic compound and those tend to have higher melting points. I predict that it will have a lower melting point than compound A. This is because according to our data, on a scale of 0-4 of conductivity, compound A rated a 3, while compound C rated a 2. This shows that compound a is more conductive than compound C. This means that compound A has a stronger bond, where less energy can be lost in the process of transferring electricity. In terms of melting point, compounds with tighter bonds have higher melting points because it takes more heat and energy to break them apart. Compound C has a weaker bond than compound A, so we can infer that it will also have a lower melting point.

Which do you think would be more dangerous near an open flame, an ionic or a covalent compound? Why? (be sure to explain what danger means to you) (3 pts)
To me, danger means being exposed to hazardous gasses and fumes.

It also means getting brain damage.Taking this into consideration, I think that a covalent compound would be more dangerous because in general covalent compounds are more volatile. This would mean that when the covalent compound heats up, the atoms would become move around becoming agitated. The weak bonds of the covalent compound would break, and therefore make the substance even more volatile. The vapors produced would reach your nose, get inhaled and cause brain damage. Acetone for example, is a covalent compound which consists of three carbon atoms, six hydrogen atoms, and one oxygen atom all sharing electrons. Acetone is dangerous near a fire: it is extremely flammable because , its volatile vapors can “cause dry cracked skin and harm the nervous system,” according to

msdsonline.com.

Which type of compound, ionic or covalent, would you expect to have a higher boiling point? Why? (3 pts)
I would expect that an ionic bond would have a higher boiling point. Since ionic bonds are held together by a strong positive and negative charge, it would take a lot of energy and heat to break them apart. Covalent bonds on the other hand are weaker. Their sharing of electrons means that they cluster and float around each other, instead of sticking together like ionic compounds. Their clusters could be easily broken, when the heat agitates them making them move around. This movement would break covalent bonds, and therefore, melt the compound.

Suppose you had a sample of two compounds mixed together. Both compounds consist of coarse, granular, yellow crystals. You know that one of the compounds is ionic and the other is covalent. How might you quickly separate or identify the two compounds? Be specific! (Hint: remember what you learned in the AE and CSI Labs) (3 pts)

You would pour the mix of two compounds containing both covalent and ionic bonds in a beaker containing distilled water. Then you would use a glass stirring rod and mix the two compounds into the water. You will be able to identify the covalent compound, because it will be less soluble than the ionic compound. In other words, after stirring for a while, you would notice that half of the compound mix would disappear (dissolve into the water). This compound is the ionic compound, since it will break apart and bond with other atoms in the water. The other half would probably still be solid; this is the covalent compound, since covalent bonds share electrons and would not be affected by the positive and negatively charged parts of the water.