Chapter 2 - Measurements & Problem Solving

Question 1

Which interpretation is more precise: 10g or 10.0g of gold?

Answer 1

10.0g

Question 2

Which reported measurement is more precise: 10.00g or 10.0g

Answer 2

10.00g

Question 3

Which digit is an estimate, and which ones are certain?

a) 1.2 g
b) 1.26 g

Answer 3

a. 1.2 - 1 is certain, 2 is an estimate
b. 1.26 - 1 and 2 is certain, 6 is an estimate

We know this because the last number is the estimate

Question 4

If a balance has markings every 1 g, where do we estimate to (tenths/hundredths/thousandths; etc) - why?

Provide example

Answer 4

If a balance has markings every 1 g, we estimate to the tenth place because each mark is a gram - it’s not as precise, so we cannot be certain of the last digit. The larger of a measurement taken, the smaller the reported # should be.

ex: 1.5 g is reported instead of 1.54 g

Question 5

If a balance has markings every 10 g, where do we estimate to (tenths/hundredths/thousandths; etc) - why?

Provide example

Answer 5

If a balance has markings every 0.1 g (a marking for every tenth of a gram), we estimate to the hundredths because the balance is precise and certain up until the tenths.

ex: we report 1.26g because we are certain up until the tenths