Notation

[Alexandra Carpenter 1G]

In problem #9b for Chapter 8, "The internal energy of a system increased by 982 J when it absorbed 492 J of heat. (a) Was work done by or on the system? (b) How much work was done?", is there a specific reason the answer is in scientific notation, instead of just 490 J? Or is it just a preference in notation?

[Audrey Goodman 1F]

I believe it's written in scientific notation in order to show how many sig figs there are. In the question, each value has 3 sig figs, but the final answer written as 490 J shows only 2 sig figs. Writing the answer in scientific notation or writing the answer as 490. J will show the correct number of sig figs.

[Andrea ORiordan 1L]

You could feasibly write the answer either way as long as you included the correct number of sig figs. I believe it's just the author's preference.

[Chris Lamb 1G]

Scientific notation is often used to remove any ambiguity about the number of sig-figs.

[andrewr2H]

Yes, so long as the correct number of sig figs is used, either way should technically be correct. Scientific notation can just be useful in avoiding having to write out a large number of zeroes and, as already mentioned, in removing ambiguity surrounding the number of sig figs.