Question

calculate the formula mass for hydroiodic acid. express your answer in atomic mass units to two decimal places. formula mass = amu

Explanation:

Step1: Identify the formula of hydroiodic acid

Hydroiodic acid has the formula \( HI \). This is because it is a binary acid composed of hydrogen (\( H \)) and iodine (\( I \)).

Step2: Find the atomic masses of H and I

The atomic mass of hydrogen (\( H \)) is approximately \( 1.008 \) amu, and the atomic mass of iodine (\( I \)) is approximately \( 126.90 \) amu.

Step3: Calculate the formula mass

To find the formula mass of \( HI \), we add the atomic masses of hydrogen and iodine. So, formula mass \( = \) atomic mass of \( H \) \( + \) atomic mass of \( I \).
Substituting the values, we get: \( 1.008 + 126.90 = 127.908 \) amu.

Step4: Round to two decimal places

Rounding \( 127.908 \) to two decimal places gives \( 127.91 \) amu.

Answer:

\( 127.91 \) amu