Question

Which of the following measurements has one significant figure?

0.0501 g

5.1 x 10-6g

6.02 x 1023g

100 g

Answer 1

I won't give you the answer because it is very simple. Use these to find your answer.
1) ALL non-zero numbers (1,2,3,4,5,6,7,8,9) are ALWAYS significant.
2) ALL zeroes between non-zero numbers are ALWAYS significant.
3) ALL zeroes which are SIMULTANEOUSLY to the right of the decimal point AND at the end of the number are ALWAYS significant.
4) ALL zeroes which are to the left of a written decimal point and are in a number >= 10 are ALWAYS significant.