What is the chemical name of the compound NH4SCN?

What is the chemical name of the compound NH4SCN? (1) ammonium thiocyanate (2) ammonium cyanide (3) nitrogen hydrogen cyanide (4) nitrogen hydrogen sulfate Answer: (1) ammonium thiocyanate Explanation: In order to name a compound, we must first figure out whether it is ionic or covalent. Ionic compounds can be divided into three categories: metal + nonmetal, meta+ polyatomic ion, polyatomic ion+ polyatomic ion, polyatomic ion + nonmetal. Covalent compounds consist of 2 nonmetals. What is a polyatomic ion? It is an ion consisting of 2 or more elements. The reference table has Table E, Selected Polyatomic ions. If we look at Table E, we can see that NH4+ is a polyatomic ion and so is SCN-. Si

Which electron configuration represents the electrons in an atom of sulfur in an excited state?

Which electron configuration represents the electrons in an atom of sulfur in an excited state? (1) 2 – 8 – 6 (2) 2 – 7 – 7 (3) 2–8– 7 (4) 2–7– 8 Answer : 2) 2-7-7 Explanation: We must first look at the Periodic Table at the Reference Table, and find Sulfur. Sulfur's electron configuration is 2-8-6 according to the Reference Table. An excited state is a state in which an electron jumps to a higher energy level, while the ground state is the lowest energy most stable state for electrons. Now, lets look at our answer choices. Choice 1 is the ground state electron configuration for Sulfur , and is therefore wrong. For choice 2, 2-7-7, is the excited electron configuration since one electron fro

What is the color of bromcresol green indicator in a solution with a pH value of 2.0?

What is the color of bromcresol green indicator in a solution with a pH value of 2.0? (1) blue (2) green (3) red (4) yellow Answer: Choice 4 Solution: An indicator allows us to figure out the pH range of the solution and whether it is acidic or basic. To do this problem, we need to look at Table M of the Regent Reference Table, Common Acid–Base Indicators. According to the table, bromcresol green, has a pH range for color change of 3.8-5.4 and the color change is yellow to blue. Therefore, a solution whose pH is less than 3.8 will have a yellow color with bromcresol green indicator. On the other hand, a solution whose pH is higher than 5.4 will have a blue color. In this question, the pH val