2.2 chromium has four naturally-occurring isotopes: 4.34% of 50cr, with an atomic weight of 49.9460 amu; 83.79% of 52cr, with an atomic weight of 51.9405 amu; 9.50% of 53cr, with an atomic weight of 52.9407 amu; and 2.37% of 54cr, with an atomic weight of 53.9389 amu. on the basis of these data, confirm that the average atomic weight of cr is 51.9963 amu.

Average atomic mass  = 51.9963 amu

Explanation:

Given data:

Abundance of Cr⁵⁰ with atomic mass= 4.34% ,  49.9460 amu

Abundance of Cr⁵² with atomic mass = 83.79%,  51.9405 amu

Abundance of Cr⁵³ with atomic mass =9.50%,  52.9407 amu

Abundance of Cr⁵⁴ with atomic mass  = 2.37%,   53.9389 amu

Average atomic mass = 51.9963 amu

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass +n)  / 100

Average atomic mass  = (4.34×49.9460)+(83.79×51.9405) +(9.50×52.9407)+ (2.37×53.9389) / 100

Average atomic mass =  216.7656 + 4352.0945 + 502.9367 +127.8352 / 100

Average atomic mass  = 5199.632 / 100

Average atomic mass  = 51.9963 amu

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

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