Is my electronic textbook incorrect?

[Qube]

Is it just me, but if you multiply anything by 100% you'll end up with the same number?

I believe the authors meant to write 100, not 100%.

This is from 5 steps to a 5 AP Chem.
[PLAIN]http://i.min.us/icDcjc.png

 

[Ouabache]

Is it just me, but if you multiply anything by 100% you'll end up with the same number?

I believe the authors meant to write 100, not 100%.

Welcome Qube to PF Forums!

Yes you are correct. The fraction will always be less than 1 because actual yield will never exceed theoretical yield. If it does, this is good chance an error was made either in the experiment or calculations. So to express as a percentage you multiply by 100 (not 100%). Textbooks can have errors in them, they are usually fixed by the 2nd or 3rd printing.

 

[Qube]

Now that I think about it, I believe I am in error.

Suppose the actual yield was 50g, and the theoretical yield was 100g.

50% = (50/100) * 100%

50% = .5 * 1

50% = .5

I still wonder why they left the 100% in though ...

And multiplying .5 by 100 as I proposed would yield 50. 50 does not equal 50%, but the left side of the equation clearly states "% yield."

[PLAIN]http://i.min.us/icDcjc.png

 

[gb7nash]

Hi Qube,

The textbook looks fine to me.

Think of the percent sign as a unit. If I want to convert .5 to percent, multiplying by 100 will only give me 50, which only means that I multiplied .5 by 100. If you want to convert .5 to a percentage, multiply .5 by 100% and you'll get 50% which is the desired result.

And multiplying .5 by 100 as I proposed would yield 50. 50 does not equal 50%, but the left side of the equation clearly states "% yield."

Exactly what I'm thinking. The left side of the equation says % yield, which means you'll need a percentage sign on the right side.

 

[Ouabache]

If I want to convert .5 to percent, multiplying by 100 will only give me 50,

Actually you get 50% because it is given you are calculating % yield.

I have seen both notations, multiplying by "100" and "100%." but I find the later
to be ambiguous. A valid interpretation (as qube noted) 100% = 1, but multiplying
by one does not give you the correct answer as a percentage.