November 17, 2019

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 io...

November 13, 2019

 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 g...

November 11, 2019

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 co...

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