Using the example above as a guide, calculate the atomic mass of sulfur if
95.00% of all sulfur atoms have a mass of 31.972 amu
0.76% have a mass of 32.971 amu
4.22% have a mass of 33.967 amu
Question 10 options:
69.765 amu
56.865 amu
34.313 amu
32.057 amu
To calculate the atomic mass of sulfur, we can use the weighted average formula:
Atomic mass = (% of isotope 1 × mass of isotope 1) + (% of isotope 2 × mass of isotope 2) + (% of isotope 3 × mass of isotope 3)
Plugging in the given values:
Atomic mass = (95.00% × 31.972 amu) + (0.76% × 32.971 amu) + (4.22% × 33.967 amu)
Atomic mass = (0.9500 × 31.972 amu) + (0.0076 × 32.971 amu) + (0.0422 × 33.967 amu)
Atomic mass ≈ 30.373 + 0.2510076 + 1.433274
Atomic mass ≈ 32.057 amu
Therefore, the atomic mass of sulfur is approximately 32.057 amu.
Using the example above as a guide, calculate the average atomic mass for the mystery element shown below. Use that value to identify the element on the periodic table.
one has a mass of 30.973 amu and 99.0% abundance
one has a mass of 31.973 amu and 0.8% abundance
one with a mass of 26.973 amu and 0.2% abundance
Calculate the average atomic mass to determine which which element this is.
Question 11 options:
Phosphorus
Sulfur
Chlorine
Iron
To calculate the average atomic mass for the mystery element, we can use the same weighted average formula as before:
Average atomic mass = (% of isotope 1 × mass of isotope 1) + (% of isotope 2 × mass of isotope 2) + (% of isotope 3 × mass of isotope 3)
Plugging in the given values:
Average atomic mass = (99.0% × 30.973 amu) + (0.8% × 31.973 amu) + (0.2% × 26.973 amu)
Average atomic mass = (0.990 × 30.973 amu) + (0.008 × 31.973 amu) + (0.002 × 26.973 amu)
Average atomic mass ≈ 30.663 + 0.255784 + 0.053946
Average atomic mass ≈ 30.97273 amu
Therefore, the average atomic mass for the mystery element is approximately 30.97273 amu. Comparing this value to the atomic masses on the periodic table, we find that this value matches the atomic mass of Phosphorus (P) closely, which is 30.97376 amu. Therefore, the mystery element is most likely Phosphorus.
To calculate the atomic mass of sulfur, we need to find the weighted average of the different isotopes present.
1. Multiply the mass of each isotope by its percent abundance:
(0.9500 * 31.972 amu) + (0.0076 * 32.971 amu) + (0.0422 * 33.967 amu)
2. Add up the products from step 1:
(0.9500 * 31.972 amu) + (0.0076 * 32.971 amu) + (0.0422 * 33.967 amu) = 30.3736 amu + 0.2508016 amu + 1.4310774 amu = 32.055478 amu
Therefore, the atomic mass of sulfur is approximately 32.055 amu.
The closest option is 32.057 amu.
To calculate the atomic mass of sulfur, you need to multiply the percentage of each isotope by its respective atomic mass and then sum them up.
Step 1: Calculate the contribution of each isotope:
- 95.00% of sulfur atoms have a mass of 31.972 amu: (95.00/100) x 31.972 amu = 30.3724 amu
- 0.76% have a mass of 32.971 amu: (0.76/100) x 32.971 amu = 0.2505716 amu
- 4.22% have a mass of 33.967 amu: (4.22/100) x 33.967 amu = 1.432334 amu
Step 2: Sum up the contributions:
30.3724 amu + 0.2505716 amu + 1.432334 amu = 32.0552956 amu
Therefore, the atomic mass of sulfur is approximately 32.057 amu, which corresponds to option (D).