Scientific Measurements Dimensional Analysis Part 1

Starter It would take 3,010,000,000,000,000,000,000,000,000 candles to reproduce sunlight. What is this number in scientific notation? Convert the following temperature to kelvin: 113oC. A liquid has a volume of 4mL and a mass of 24 grams. What is the density of the liquid?

Starter It would take 3,010,000,000,000,000,000,000,000,000 candles to reproduce sunlight. What is this number in scientific notation? 3.01 x 1027 Convert the following temperature to kelvin: 113oC. A liquid has a volume of 4mL and a mass of 24 grams. What is the density of the liquid?

Starter It would take 3,010,000,000,000,000,000,000,000,000 candles to reproduce sunlight. What is this number in scientific notation? 3.01 x 1027 Convert the following temperature to kelvin: 113oC. (K = oC + 273.15). 386.15 k A liquid has a volume of 4mL and a mass of 24 grams. What is the density of the liquid?

Starter It would take 3,010,000,000,000,000,000,000,000,000 candles to reproduce sunlight. What is this number in scientific notation? 3.01 x 1027 Convert the following temperature to kelvin: 113oC. (K = oC + 273.15). 376.15 k A liquid has a volume of 4mL and a mass of 24 grams. What is the density of the liquid? 6 g/mL

Converting Metric Measurements There are 3 ways to convert between units: Multiplication and Division Decimal Movement Conversion Factors

Converting Metric Measurements For all methods it is important to learn the most common prefixes

Converting Metric Measurements Multiplication and Division Learn the most common prefixes Kilo - 1,000 times larger Hecto - 100 times larger Deca - 10 times larger Deci - 10 times smaller Centi - 100 times smaller Milli - 1,000 times smaller

Converting Metric Measurements Multiplication and Division 2. Put the base unit you are measuring in the middle under “unit”

Converting Metric Measurements Multiplication and Division 3. Determine whether the units you want are larger or smaller than the units you have

Converting Metric Measurements Multiplication and Division 4. Determine the numerical relationship between the units you have and the units you want.

Converting Metric Measurements Multiplication and Division 5. For “large to small” conversions, multiply by the appropriate power of ten. For “small to large” conversions, divide by the appropriate power of ten.

Converting Metric Measurements Decimal Movement 1. Determine the direction and size of the conversion.

Converting Metric Measurements Decimal Movement 2. Move the decimal point in your measurement.

Converting Metric Measurements Decimal Movement 3. Add zeros as necessary

Metric Conversion Practice Problems How many liters are in 872 milliliters?

Metric Conversion Practice Problems How many liters are in 872 milliliters? 0.872 L

Metric Conversion Practice Problems How many grams are in 0.679kg?

Metric Conversion Practice Problems How many grams are in 0.679kg? 679g

Metric Conversion Practice Problems How many kiloliters are in 4.32×105 liters?

Metric Conversion Practice Problems How many kiloliters are in 4.32×105 liters? 432 kl or 4.32 x 102 kl

Dimensional Analysis & Conversion Factors The procedure we use to convert between units in solving chemistry problems is called dimensional analysis. Conversion Factor: a factor used to convert between two separate units.

Information given x conversion factor = desired unit Conversion Factors Conversion Factor: a factor used to convert between two separate units 1 in = 2.54 cm Information given x conversion factor = desired unit desired unit given unit given unit x = desired unit

Conversion Factors Problem: convert 17.6 in to cm 17.6 in x 2.54 cm Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit Problem: convert 17.6 in to cm 17.6 in x 2.54 cm 1 in = x cm

Conversion Factors Conversion Factor: 1 in = 2.54 cm desired unit Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit 2.54 cm 1 in Problem: convert 17.6 in to cm 17.6 in x = x 17.6 x 2.54 cm =

Conversion Factors Conversion Factor: 1 in = 2.54 cm desired unit Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit 2.54 cm 1 in Problem: convert 17.6 in to cm 17.6 in x = x 17.6 x 2.54 cm = 44.7cm

Conversion Factors Conversion Factor: 1 in = 2.54 cm desired unit Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit 1 in 2.54 cm Problem: convert 57.9 cm to in 57.9 cm x = x in

Conversion Factors Conversion Factor: 1 in = 2.54 cm desired unit Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit 1 in 2.54 cm Problem: convert 57.9cm to in 57.9 cm x = x

Conversion Factors Conversion Factor: 1 in = 2.54 cm desired unit Information given x conversion factor = desired unit Conversion Factor: 1 in = 2.54 cm desired unit given unit given unit x = desired unit 1 in 2.54 Problem: convert 57.9cm to in 57.9 x = 22.8 in

A Practice Problems Problem: How many feet are equal to 54.7 in? Information given x conversion factor = desired unit Conversion Factor: 1 ft = 12 in desired unit given unit given unit x = desired unit Problem: How many feet are equal to 54.7 in?

A Practice Problems Problem: How many feet are equal to 54.7 in? Information given x conversion factor = desired unit Conversion Factor: 1 ft = 12 in desired unit given unit given unit x = desired unit Problem: How many feet are equal to 54.7 in? 4.56 ft

Problem: convert 7.8 km to miles Practice Problems Information given x conversion factor = desired unit Conversion Factor: 1 km = 0.6214 mi desired unit given unit given unit x = desired unit Problem: convert 7.8 km to miles

Problem: convert 7.8 km to miles Practice Problems Information given x conversion factor = desired unit Conversion Factor: 1 km = 0.6214 mi desired unit given unit given unit x = desired unit Problem: convert 7.8 km to miles 4.8 mi

C Practice Problems Information given x conversion factor = desired unit Conversion Factors: 1lb = 453.6g 1mg = 1x10−3 desired unit given unit given unit x = desired unit Problem: a person’s average daily intake of glucose is 0.0833 pound. What is this mass in mg?

C Practice Problems Information given x conversion factor = desired unit Conversion Factors: 1lb = 453.6g 1mg = 1x10−3 desired unit given unit given unit x = desired unit Problem: a person’s average daily intake of glucose is 0.0833 pound. What is this mass in mg? 3.78 x104

D Practice Problems Problem: convert 194 cm to feet. Information given x conversion factor = desired unit Conversion Factors: 1 in = 2.54 cm 1 ft = 12 in desired unit given unit given unit x = desired unit Problem: convert 194 cm to feet.

D Practice Problems Problem: convert 194 cm to feet. 6.36 ft Information given x conversion factor = desired unit Conversion Factors: 1 in = 2.54 cm 1 ft = 12 in desired unit given unit given unit x = desired unit Problem: convert 194 cm to feet. 6.36 ft

E Practice Problems Information given x conversion factor = desired unit Conversion Factors: 1 quart = 4 cups 1L = 1.057 qt desired unit given unit given unit x = desired unit Problem: A recipe calls for making creamy pasta sauce calls for 0.75 liters of cream. Your measuring cup measures only in cups. How many cups of cream should you use?

E Practice Problems Information given x conversion factor = desired unit Conversion Factors: 1 quart = 4 cups 1L = 1.057 qt desired unit given unit given unit x = desired unit Problem: A recipe calls for making creamy pasta sauce calls for 0.75 liters of cream. Your measuring cup measures only in cups. How many cups of cream should you use? 3.2 cups

Converting Metric Measurements Conversion Factors 1 km = m 1m = cm 1 hg = g 1 g = mg

Converting Metric Measurements Conversion Factors 1 km = 1000 m 1m = 100 cm 1 hg = 100 g 1 g = 1000 mg

When doing dimensional analysis REMEMBER Always write every number with its associated unit. Never ignore units; they are critical Always include units in your calculations, dividing them and multiply them as if they were algebraic quantities. Do not let units magically appear or disappear in calculations.