Question

There are four naturally occurring isotopes of the element chromium. The relative abun- dance of each is
50Cr 4.345% 52Cr 83.789% 53Cr 9.501% 54Cr 2.365%
49.946044 amu 51.940508 amu 52.940649 amu 53.93880 amu
Find the average atomic mass of chromium. 1. 53.2503 amu
2. 52.978 amu
3. 52.061 amu
4. 51.996 amu

Answer 1

Solution:
To solve this, we have to take a weighted average.

First we convert the percentages to decimals (4.345% becomes 0.04345, 83.789% becomes 0.83789, 9.501% becomes 0.09501 and 2.365% becomes 0.02365)

Second, we multiply those decimals by the masses, and add the products.


(0.04345) X (49.946044 amu) = xxxxx amu
(0.83789) X (51.940508 amu) = +yyyyyy amu
(0.09501) X (52.940649 amu) = + vvvvvv amu
(0.02365) X (53.93880 amu) = + zzzzzz amu
uuuuuu amu

Notice that the result, uuuuuu amu is close to the value reported for Boron on the periodic table.

Answer 2

The answer is 4) 51.996

Answer 3

you did the calculation or just look it at at the periodic table?

Answer 4

I did the calculation

Answer 5

good job!!!