Exams & Certification

Element A exists in three isotopic forms with masses of 21.0, 25.0 and 26.0 amu respectively. Element B also exists in three isotopic forms with masses of 22.0, 24.0 and 26.0 amu respectively. It is true that __. A) element A has a higher atomic mass than B B) element B has a higher atomic […]

Three naturally occurring isotopes exist for the hypothetical element athenium. 2.50% of athenium atoms have a relative mass of 26.0 amu, 75.0% of athenium atoms have a relative mass of 27.0 amu, and 22.5% of athenium atoms have a relative mass of 28.0 amu. What is the atomic mass of athenium? A) 26.8 amu B)

Pitch circle diameter of an involute gear is: (a) Independent of any other factor(b) Dependent on the pressure angle(c) Constant for a set of meshing gears(d) Proportional to the base diameter The correct answer and explanation is : The correct answer is: (b) Dependent on the pressure angle Explanation: Involute gears are designed based on

The isotopic mass for a particular isotope of gold is 196.9665 amu. The mass number for this gold isotope __. A) is 79 B) is 196 C) is 197 D) cannot be determined from the information given The correct answer and explanation is : The correct answer is: C) is 197 Explanation: To understand the

An isotope of which element is used as the standard for the relative mass scale for atoms? A) carbon B) oxygen C) hydrogen D) helium The correct answer and explanation is : The correct answer is A) carbon. The standard for the relative mass scale of atoms is based on the isotope carbon-12 (C-12). This

The primary structure of a protein refers to: A) the sequence of its amino acids. B) the orientation of a-helices. C) the orientation of pleated sheets. D) the orientation of peptide subunits within a complex protein. E) the placement of the protein’s active site. The correct answer and explanation is : The correct answer is

Describe what is meant by the primary structure of a protein? The correct answer and explanation is : The primary structure of a protein refers to the specific sequence of amino acids that are linked together by peptide bonds to form a polypeptide chain. This sequence is determined by the genetic code, specifically the nucleotide

The Ka for benzoic acid is 6.5 × 10−5 . Calculate the pH of a 0.10 M benzoic acid solution. The Correct Answer And Explantion is: To calculate the pH of a 0.10 M benzoic acid (C6H5COOHC_6H_5COOHC6​H5​COOH) solution, we use the acid dissociation constant (KaK_aKa​) and set up an equilibrium expression. Step 1: Write the

Which of the following represents a pair of isotopes? A) 14C, 14N B) 1H, 2H C) 32S, 32S-2 D) O2, O3 The correct answer and explanation is : The correct answer is B) 1H, 2H. Explanation: Isotopes are atoms of the same element that have the same number of protons (atomic number) but different numbers

GreenLawn Co provides landscaping services to clients. On May 1, a customer paid GreenLawn $70,000 for 6 months services in advance. GreenLawn’s general journal entry to record this transaction will include a: Debit to Unearned Revenue for $70,000.Credit to Accounts Receivable for $70,000Credit to Cash for $70,000Credit to Unearned Revenue for $70,000Debit to Accounts Receivable