How many significant digits are there in the number 204.0920?

7 significant digits

Explanation:

Significant  digits.: The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

Rules for significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant  digits.

All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant  digits.

All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant digits.

All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant digits.

All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant digits

Thus 204.0920 has 7 significant digits.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.