Question 1) Consider the following reaction of calcium hydride (CaH2) with molten sodium metal:CaH2(s) + 2 Na(l) -> 2 NaH(s) + Ca(l) Identify the species being oxidized and the species being reduced?
Question 2) Give the names to the binary compounds listed below. Classify the bonds in the following as ionic or covalent. For bonds that are covalent, indicate whether they are polar or nonpolar. Explain your answer.
a. Na2O b. CaCl2 c. NBr3 d. CS2
Please help thank you!!!!
2. Ionic bonding involves the transfer of electrons from two oppositely charged ions. This reaction usually involves a metal (electron donor) and a non-metal (acceptor).
Covalent bonding occurs between elements close to each other or of the same nature on the periodic table. Instead of transferring electrons, they share electrons.
Therefore, both a. (Na2O) and b. (CaCl2) are ionic bonds and polar, as they are from two different spectra of the periodic table, with one ion being the donor and the other being the acceptor respectively.
Both c. (NBr3) and d. (CS2) are covalent, non-polar bonds, as they are sharing electrons due to the fact that they are situated close to each other on the periodic table and do not need to transfer electrons from their valence shells, as they have similar valence shell structures.
1. The species being oxidized is Ca losing electrons and the species being reduced is Na gaining electrons.
Question 1) To identify the species being oxidized and the species being reduced in the given reaction, we need to assign oxidation numbers to each element present in the reaction. The species that increases its oxidation number is being oxidized, while the species that decreases its oxidation number is being reduced.
- In the reaction CaH2(s) + 2 Na(l) -> 2 NaH(s) + Ca(l), let's assign oxidation numbers to the elements:
- CaH2: Calcium (Ca) is in Group 2 of the periodic table, so its oxidation number is +2. Hydrogen (H) always has an oxidation number of +1 when combined with nonmetals. In a compound, like CaH2, hydrogen would usually have an oxidation number of -1 with metals. So, here hydrogen's oxidation number is -1.
- NaH: Sodium (Na) is a Group 1 element, so its oxidation number is +1. Hydrogen (H) has an oxidation number of -1 as before.
- NaH2: Sodium (Na) still has an oxidation number of +1, but hydrogen (H) now has an oxidation number of -2 to balance the overall charge of 0.
- Ca(l): Elemental calcium (Ca) has an oxidation number of 0.
Based on the changes in oxidation numbers, we can conclude:
- The species being oxidized is CaH2. The oxidation number of hydrogen (H) goes from -1 to -2, indicating an increase in oxidation number.
- The species being reduced is Na(l). The oxidation number of sodium (Na) goes from 0 to +1, indicating a decrease in oxidation number.
Question 2) Let's determine the names of the binary compounds listed and classify their bonds as ionic or covalent, indicating whether they are polar or nonpolar:
a. Na2O
- The compound Na2O includes sodium (Na) and oxygen (O). Sodium is a metal, and oxygen is a nonmetal. Based on their positions in the periodic table, Na2O is an ionic compound called sodium oxide. The bond between Na and O is ionic.
b. CaCl2
- The compound CaCl2 includes calcium (Ca) and chlorine (Cl). Calcium is a metal, and chlorine is a nonmetal. Based on their positions in the periodic table, CaCl2 is also an ionic compound called calcium chloride. The bond between Ca and Cl is ionic.
c. NBr3
- The compound NBr3 includes nitrogen (N) and bromine (Br). Both nitrogen and bromine are nonmetals. Based on their positions in the periodic table, NBr3 is a covalent compound called nitrogen tribromide. The bond between N and Br is covalent.
d. CS2
- The compound CS2 includes carbon (C) and sulfur (S). Both carbon and sulfur are nonmetals. Based on their positions in the periodic table, CS2 is a covalent compound called carbon disulfide. The bond between C and S is covalent.
Regarding the polarity of the covalent compounds:
- NBr3: The N-Br bonds are polar due to the difference in electronegativity between nitrogen and bromine.
- CS2: The C-S bonds are nonpolar because carbon and sulfur have similar electronegativities, resulting in an even distribution of electron density.
I hope this helps to clarify and guide you in finding the answers for these questions!
1.
Ca has a oxidation state of +2 on the left and zero on the right.
Na is zero on the left and +1 on the right.
Oxidation is the loss of electrons; reduction is the gain of electrons. Which lost and which gained and you have the answer.
2.
What's your problem with this question. What do you not understand?