{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

chem-201-chapter-2

# chem-201-chapter-2 - Analytical Tools Analytical Balances...

This preview shows pages 1–2. Sign up to view the full content.

9/29/11 1 Analytical Tools Analytical Balances An modern analytical balance uses a magnetic force to balance the pan and determine the mass of the sample (Figure 2-3) Analytical balances can measure to a precision of 0.0001 g (0.1 mg) Precaution to use when weighing Do not touch sample or container with fingers —the balance is precise enough to weigh finger prints Analytical Balances Precaution to use when weighing Close the doors on the balance to prevent air drafts from affecting results Correction for buoyancy—upward force by air under pan of balance = s a w a d d 1 d d 1 ' m m m = true mass of object m = mass reading from balance d a = density of air d w = density of weights (8.0 g/mL) d s = density of sample Analytical Balances Buoyancy Correction Determine true mass of a CuSO 4 5H 2 O sample with a mass reading of 0.5672 g d s = 2.284 g/mL d w = 8.0 g/mL d a = (P MW)/(RT) = (1 atm)(29 g/mol)/(.08205 Latm/molK)(298K) = 1.186 g/L

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 2

chem-201-chapter-2 - Analytical Tools Analytical Balances...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online