Silicon has three naturally occurring isotopes. Silicon-28 has a mass of 27.98 and a relative abundance of 92.23%. Silicon-29 has a mass of 28.98 and a relative abundance of 4.68%. Silicon-30 has a mass of 29.97 and a relative abundance of 3.09%. What is the weighted average atomic mass of silicon?

27.99 g/mol

28.09 g/mol

28.98 g/mol

29.00 g/mol

Question

Silicon has three naturally occurring isotopes. Silicon-28 has a mass of 27.98 and a relative abundance of 92.23%. Silicon-29 has a mass of 28.98 and a relative abundance of 4.68%. Silicon-30 has a mass of 29.97 and a relative abundance of 3.09%. What is the weighted average atomic mass of silicon?

 27.99 g/mol

 28.09 g/mol

 28.98 g/mol

 29.00 g/mol

ganeshie8 · Answer

take each isotope mass and abundance

ganeshie8 · Answer

multiply :  mass x abundance

anonymous · Answer

Okay Then What? @ganeshie8

ganeshie8 · Answer

then, add them all

ganeshie8 · Answer

27.98 x 92.23%

+

28.98 x 4.68%

+

29.97 x 3.09%

anonymous · Answer

I Got 28.09

ganeshie8 · Answer

mostly correct !

anonymous · Answer

Mostly? Does That Mean It's Not Quite Right?

ganeshie8 · Answer

idk il have to work it, but i trust your calculation lol

anonymous · Answer

Haha Okay Can You Help With One More?

ganeshie8 · Answer

sure :) and 28.09 is correct, ive checked

anonymous · Answer

In a 10-gram sample of carbon and a 10-gram sample of sulfur, how many more moles of carbon are there than sulfur?

 0.052 moles

 0.52 moles

 2.05 moles

 20.05 moles