A lab technician measures the volume of a liquid sample using a digital burette before starting a titration, and records the reading as \(27.348\) ml on the...
Question 1 Report
A lab technician measures the volume of a liquid sample using a digital burette before starting a titration, and records the reading as \(27.348\) ml on the results sheet.
- Round \(27.348\) to 1 decimal place. (1)
- Round \(27.348\) to 2 significant figures. (1)
Answer Details
Rounding to a given number of decimal places looks only at the digit immediately after the cut-off point, while rounding to a given number of significant figures counts meaningful digits starting from the first non-zero digit; applying each rule separately to the same reading, \(27.348\), gives two different rounded values.
(a) Rounding to 1 decimal place keeps one digit after the decimal point; the next digit, \(4\), rounds down, giving \(27.3\) ml. [1 mark]
(b) Rounding to 2 significant figures keeps the first two meaningful digits, \(2\) and \(7\); the next digit, \(3\), rounds down, giving \(27\) ml. [1 mark]
Both roundings happen to round down here because the digit right after the cut-off point in each case (\(4\) and then \(3\)) is less than \(5\); a digit of \(5\) or more would instead round the previous digit up.
Download The App On Google Playstore
Everything you need to excel in your exams
