Warm Up Which substance is best classified as being malleable? a)lead plate b)chocolate chip cookie c)ceramic tile d)glass panel.

Warm UpWarm Up

• Which substance is best classified as being malleable?

a) lead plateb) chocolate chip cookiec) ceramic tiled) glass panel

Chp 2 Activity 5 Investigation Chp 2 Activity 5 Investigation page 134page 134

WDYT?WDYT?Since a kilogram of feathers and a kilogram of lead have the same mass, how do they appear different and why?

InvestigationInvestigation

• You Have 20 minutes to complete Part A: 1. Copy the following data table into Log Book

Volume and Mass of WaterVolume and Mass of WaterMass of

Graduated Cylinder

Volume of water (mL)

Mass of graduated

cylinder and water (g)

Mass of water (g)

MassVolume(g/mL)

1.

2.

3.

4.

5.

Independent Independent WorkWork

• Checking Up Checking Up – Page 140– Questions 1 - 4

Chemistry In ActivityChemistry In ActivityChem Saver Chem Saver Pages 7Pages 7

• Precision vs. Accuracy– AccuracyAccuracy refers to how close a measuredmeasured

value agrees with the correct value.– PrecisionPrecision refers to how closely individual

measurements agree with each other. A precise measurement is one that we can make to a large number of decimal places.

Beaker Graduated Cylinder

BuretteBurette

Chemistry In ActivityChemistry In ActivityChem Saver Chem Saver Pages 7Pages 7

1045.010

The decimal point is present!Go to the Pacific Ocean and start walking across the United States until you hit a nonzero digit. After you hit the first nonzero digit, count all digits after that. These are all significant.

7 Significant Figures

0.00560

The decimal point is present!Go to the Pacific Ocean and start walking across the United States until you hit a nonzero digit. After you hit the first nonzero digit, count all digits after that. These are all significant.

3 Significant Figures

1045000

The decimal point is absent!Go to the Atlantic Ocean and start walking across the United States until you hit a nonzero digit. After you hit the first nonzero digit, count all digits after that. These are all significant.

4 Significant Figures

• Significant DigitsSignificant Digits– If Decimal absentabsent Start from the AtlanticAtlantic go to the

first whole number count it and every number to the left.• 35360 = ______

– If decimal PresentPresent Start from the PacificPacific go to the first whole number count it and every number to the right.• 0.00543 = ______

Chemistry In ActivityChemistry In ActivityChem Saver Chem Saver Pages 8Pages 8

4

3

Practice Counting Significant Figures

Measurement1.0070 m17.10 Kg100,890 L3.29x103 seconds0.0054 cm3,200,000 ml

Significant Figures545322

3.013 rounded to the hundredths is

3.01

3.015 rounded to the hundredths is

3.02

3.045 rounded to hundredths is

3.05

• 761.50

• 14.334

• 10.44

• 10789

• 8024.50

• 203.514

Practice Rounding to 3 Significant Figures762762

14.3

10.4

10800

8020

204

Chemistry In ActivityChemistry In ActivityChem Saver Chem Saver Pages 8Pages 8

MULTIPLYING and DIVIDING using Significant Figures

So your answer can only have ________ Significant digits

________ Has the least number of significant Digits 5946.50525 = ________

Example:

23.37 x 3.10 x 85.75 = 5946.505254 3 4

3.10 3

5950

Chemistry In ActivityChemistry In ActivityChem Saver Chem Saver Pages 8Pages 8

So 20.69 must be rounded to _____ decimal place

ADDING and SUBTRACTING using Significant Figures

________ Has the least number of decimal places

20.69 = _________

Example:3.76 + 14.83 + 2.1 = 20.69

2 2 1

2.1

1

20.7

Independent Independent WorkWork

• Accuracy & Precision WorksheetAccuracy & Precision Worksheet