Review: Measurement and Sig Figs

Review: Measurement and Sig Figs

by Kimberly O'Reilly

An element contains just one type of atom. Elements can NOT be broken down. ​

​Compounds contain 2 or more different atoms chemically bonded. Compounds can be decomposed chemically.

​

Elements vs. Compounds

​

Multiple Choice

Carbon is considered an element, while carbon dioxide is considered a compound. This is because carbon dioxide is ---

• a gas at room temperature.

• made of two different elements.

• given off by green plants.

• useful to human beings

Multiple Choice

Is sugar (C₁₂H₂₂O₁₁) an element or a compound?

• Element
• Compound

​Element Symbols!

Know your element symbols! See pages 3-4 in the Matter and Measurement packet for the list!

Multiple Choice

What is the element symbol for Krypton?

• K

• Kr

• P

• Pr

Multiple Choice

What is the element symbol for mercury?

• Mo

• Ag

• Au

• Hg

Multiple Choice

What is the element symbol for lead?

• Po

• Li

• Hg

• Pb

Multiple Choice

What is the element symbol of Phosphorus?

• P

• K

• Pt

• Po

​Making Measurements w Sig Figs

​Be sure to read all of the digits (numbers) from the measuring device and then estimate one digit (number)!

Multiple Choice

Which is a correct measurement made with the measuring device shown? 

• 1.3 cm

• 1.36 cm

• 1 cm

• 1.030 cm

Multiple Choice

Which is a correct measurement made with the measuring device shown? 

• 4.5 cm

• 4.50 cm

• 4.0 cm

• 4 cm

Multiple Choice

Which is a correct measurement made with the measuring device shown? 

• 20 mL

• 21 mL

• 21.60 mL

• 21.6 mL

​Determining the number of sig figs in a measurement . . .

​Use your "zero" rules!

• ​Nonzero digits always significant!

• ​In between zeros always significant!

• ​Trailing zeros only significant when a decimal point is present!

• ​Leading zeros are never significant!

​Determining the number of sig figs in a measurement . . .

​Use your Atlantic-Pacific Rule!

Multiple Choice

How many significant figures does the measurement 10.1 cm have?

• 1

• 2

• 3

• 0

Multiple Choice

How many significant figures does the measurement 0.010 cm have?

• 1

• 2

• 3

• 4

Multiple Choice

How many significant figures does the measurement 10,080 sec have?

• 2

• 3

• 4

• 5

Multiple Choice

How many significant figures does the measurement 1.90 × 10⁸ grams have?

• 1

• 2

• 3

• 4

Multiple Choice

How many significant figures does the measurement 0.040170 L have?

• 4

• 5

• 6

• 7

​Calculations with Sig Figs

​Know your rules for adding/subtracting and multiplying/dividing!

​Calculations with Sig Figs

​Know your rules for adding/subtracting and multiplying/dividing!

​Density Calculations

​The formula for calculating density is on Reference Table T!

Multiple Choice

Perform the calculation to the correct number of significant figures with the correct unit.

12.34 g + 1.234 g + 0.1234 g =

• 13.7 g

• 13.70 g

• 13.697 g

• 13.6974 g

Multiple Choice

Perform the calculation to the correct number of significant figures with the correct unit.

12.34 cm × 1.234 cm × 0.1234 cm=

• 1.8790809 cm³

• 1.879081 cm³

• 1.9 cm³

• 1.879 cm³

Multiple Choice

Calculate the volume of the cube to the correct number of significant figures. Assume units are cm. 

• 144 cm³

• 100 cm³

• 140 cm³

Multiple Choice

A sample of copper has a mass of 89.57 grams and a volume of 10.0 mL. Calculate the density of the copper sample to the correct number of sig figs and with the correct unit!

• 8.96 g/mL

• 8.957 g/mL

Multiple Choice

What is the volume of object X to the correct number of significant figures?

• 25 mL 

• 25.0 mL

• 65.0 mL

• 90.0 mL

Multiple Choice

If the mass of Object X is 100.00 grams, its density is . . .

• 4 g/mL

• 4.0 g/mL

• 4.00 g/mL

• 4.000 g/mL

Multiple Choice

Perform the calculation to the correct number of significant figures with the correct unit.

The density of platinum is 21.45 g/cm³. How much space would a 107.25 g sample of platinum take up?

• 2301 cm³

• 0.2000 cm³

• 5.000 cm³

• 5.0 cm³

​Accuracy vs. Precision

​

​Percent Error Calculations

​The formula for calculating % error is on Reference Table T!

Multiple Choice

Liam uses a thermometer and finds the boiling point of ethyl alcohol to be 75.0^o C.  He looks in Mrs. O'Reilly's Handbook of Chemistry and Physics and finds that the actual boiling point of ethyl alcohol is 80.0^oC.  What is his percent error?

 

• 6.25%

• 6.3%

• 25%

• 25.0%

Multiple Choice

A student measures the mass of a sample as 25.00 grams in chemistry lab. What is this mass expressed in milligrams?

• 0.02500 mg

• 2.500x10⁴mg

• 0.2500 mg

• 2.500x10³ mg

​1) Set up conversion factor with units.
2) Place a 1 in front of the larger unit.
3) Place a 1 in front of the smaller unit and add the number of zeros that separate the two units on a number line.
4) Perform the math!

​Metric Conversions using Dimensional Analysis

Multiple Choice

Convert 4.17 Liters to milliliters.

• 0.00417 mL

• 41.7 mL

• 4,170 mL

• 41,700 mL

Multiple Choice

Convert 12.28 grams to kilograms.

• 12,280 kg

• 0.01228 kg

• 12,280 kg

• 0.1228 kg