Textbook Problem E.7

[Vanessa_Ong_3F]

For question E.7 in the textbook, I understand that we take 2.1 x 10^9 x (1 mol/ 6.022 x 10^23) but for some reason my calculator keeps calculating 3.5 x 10^31 instead of 3.5 x 10^-15? Does anyone know the reason for this?

[Lauren Woodward 1I]

I would guess that you missed a pair of parenthesis around each number in scientific notation. Without the parenthesis, the order of operations would be calculated left to right which yields the answer you're getting. If you have a calculator with a fraction bar I would suggest using that, as you don't have to worry as much about parentheses.

[Shannon Lau 14B - 1H]

I think a common mistake is when inputting 2.1 x 10^9 x (1 mol/ 6.022 x 10^23) you should make sure that the (6.022 x 10^2) is in its own parenthesis so you aren't dividing the 1 mol by 6.022 and multiplying it by 10^23. Make sure you use the fraction feature and not just the division sign as well.