The relative atomic mass of a sample of chlorine which contains 75.78% chlorine -35 and 24.22% chlorine-37 is ____.
.7578*35 + .2422*37 = 35.48
This is very close to the atomic mass of Cl (35.5) you will find listed in the periodic table.
To find the relative atomic mass of the sample, we need to calculate the weighted average of the two isotopes based on their percent abundances.
Step 1: Write down the information given:
Percent abundance of chlorine-35 = 75.78%
Percent abundance of chlorine-37 = 24.22%
Step 2: Calculate the weighted average:
Relative atomic mass = (percent abundance of chlorine-35 × atomic mass of chlorine-35) + (percent abundance of chlorine-37 × atomic mass of chlorine-37)
Step 3: Look up the atomic masses of the isotopes:
Atomic mass of chlorine-35: 35.00 amu
Atomic mass of chlorine-37: 37.00 amu
Step 4: Substitute the values into the formula:
Relative atomic mass = (0.7578 × 35.00) + (0.2422 × 37.00)
Step 5: Calculate the expression:
Relative atomic mass = (26.5365) + (8.984)
Step 6: Add the values:
Relative atomic mass = 35.5205 amu
Therefore, the relative atomic mass of the sample is approximately 35.5205 amu.
To find the relative atomic mass of a sample containing different isotopes, you need to calculate the weighted average of the atomic masses of the isotopes present.
1. Identify the atomic masses of the isotopes:
- Chlorine-35: has an atomic mass of 35.
- Chlorine-37: has an atomic mass of 37.
2. Determine the percentages of each isotope in the sample:
- Chlorine-35: 75.78%
- Chlorine-37: 24.22%
3. Calculate the weighted average using these values:
(75.78% * 35) + (24.22% * 37)
= (0.7578 * 35) + (0.2422 * 37)
= 26.583 + 8.985
= 35.568
Therefore, the relative atomic mass of the sample of chlorine, containing 75.78% Chlorine-35 and 24.22% Chlorine-37, is approximately 35.568.