Dimensional Analysis In Chemistry and everyday life you will often need to express a measurement using a different unit than the one that was initially used To convert between units we can use ID: 296929
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Slide1
Notes: Dimensional AnalysisSlide2
Dimensional Analysis
In Chemistry and every-day life you will often need to express a measurement using a different unit than the one that was initially used.
To convert between units we can use
dimensional analysis
.
Dimensional analysis
is a way to analyze and solve problems by using the
units
, or dimensions, of the measurements.Slide3
Dimensional Analysis
To convert units,
conversion factors
are used
.
Conversion factors are equalities arranged as a ratio with different units.For every equality, you can write two conversion factors Ex. 1 dollar = 4 quarters
Read as “one dollar per four quarters” or “four quarters per dollar
”Slide4
Dimensional Analysis
Correctly setting up dimensional analysis problems is essential to being able to solve them.
Steps of Dimensional Analysis
1.
Write down the conversion factors you can use2. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide5
Dimensional Analysis
Ex. How many dollars are in 27 quarters?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide6
Dimensional Analysis
Ex . How many dollars are in 27 quarters?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide7
Dimensional Analysis
Ex . How many quarters are in 12.75 dollars?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide8
Dimensional Analysis
Ex . How many quarters are in 12.75 dollars?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide9
Dimensional Analysis
Ex. Your car gets 19.5 miles per gallon. How many miles can you drive on 12.2 gallons of gas?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide10
Dimensional Analysis
Ex. Your car gets 19.5 miles per gallon. How many miles can you drive on 12.2 gallons of gas?
1.
Write down the conversion factors you can use
2
. Write what is unknown equal to the known.3. Multiply by the correct conversion factor4. Cancel the units and do the math.Slide11
Dimensional Analysis
Sometimes we need to use several conversion factors in a row. Usually a go-between unit is used.
Ex. How many seconds are in 5.6 hours?
1.
Write down the conversion factors you can use
2. Write what is unknown equal to the known.3. Multiply by the correct conversion factorCancel the units and do the math.Slide12
Dimensional Analysis
Sometimes we need to use several conversion factors in a row. Usually a go-between unit is used.
Ex. How many seconds are in 5.6 hours?
1.
Write down the conversion factors you can use
2. Write what is unknown equal to the known.3. Multiply by the correct conversion factorCancel the units and do the math. 1 minute = 60 seconds 1 hour = 60 minutes
note: 2 sig figs needed in answer!!Slide13
Dimensional Analysis
Sometimes we need to use several conversion factors in a row. Usually a go-between unit is used.
Ex. How many hours in 12,894 seconds?
1.
Write down the conversion factors you can use
2. Write what is unknown equal to the known.3. Multiply by the correct conversion factorCancel the units and do the math.Slide14
Dimensional Analysis
Sometimes we need to use several conversion factors in a row. Usually a go-between unit is used.
Ex. How many hours in 12,894 seconds?
1.
Write down the conversion factors you can use
2. Write what is unknown equal to the known.3. Multiply by the correct conversion factorCancel the units and do the math. 1 minute = 60 seconds 1 hour = 60 minutes