A silicon-containing ore has 92% 28^S, 5% 29^Si and 3% 30^Si. Calculate the relative atomic mass of the silicon.

A silicon-containing ore has 92% 28^S, 5% 29^Si and 3% 30^Si. Calculate the relative atomic mass of the silicon.

A. 14.00

B. 29.00

C. 28.11

D. 28.00

We are asked to calculate the relative atomic mass (RAM) of silicon using the isotopic abundances. Let's do it step by step.

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Step 1: Recall the formula

RAM = summation (isotope mass * abundance)/{100}

Here, the isotopes are:

• (^{28}{Si}) → 92%

• (^{29}{Si}) → 5%

• (^{30}{Si}) → 3%

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Step 2: Multiply masses by their percentages

^{28}Si}: 28 * 92 = 2576
^{29}{Si}: 29 * 5 = 145
^{30}{Si}: 30 * 3 = 90

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Step 3: Add them up

2576 + 145 + 90 = 2811

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Step 4: Divide by 100 (since abundances are in %)

{RAM} = {2811}/{100} = 28.11

✅ Correct answer: C. 28.11

PQN: 29