Chapter 1.2 - Problem Solving

CHEM-1409

Accuracy

How close to the true value a given measurement is.

Compare result to reported value

Precision

How well a number of independent measurements agree with each other.
Subtract low from high measurement and compare
to other groups results.

Sig Figs in Multiplication or Division

For multiplication or division, the number of significant figures in the result is the same as that in the measurement with the smallest number of significant figures

Exact numbers do not limit the number of significant figures in a calculation

Sig Figs in addition or subtraction

For addition or subtraction, the limiting term is the one with the smallest number of digits past the decimal

Exact numbers do not limit the number of significant figures in a calculation

Rounding If the digit to be removed is less than 5

If the digit to be removed is less than 5, the preceding digit stays the same

Rounding If the digit to be removed is greater than 5

If the digit to be removed is greater than 5, the preceding digit is increased by 1

If the digit to be removed is 5

If the digit to be removed is 5 with nothing following, round up or round down so that the answer is an even number.