Chemistry 300 Unit 7:

Dimensional Analysis & The Mole!

1 Mole = 6.022 X 1023

or

602,200,000,000,000,000,000,000

Dimensional Analysis

Review of Scientific Notation and SI Units

  1. Express the following numbers using scientific notation:

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a.Example: 15,000 = 1.5 x 104

b.0.087

c.1530

d.0.833

e.12, 212,000

f.0.000774

g.71.9

h. 0.0000045

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  1. Express the following numbers in expanded (ordinary) form:
  1. Example: 3.825x103 = 3,825
  2. 2.35x104
  3. 9.3x10-2
  4. 2.44x10-4
  1. Calculate answers for the following and write them in standard scientific notation and with the proper number of significant figures:
  1. Example: 72 / 83 = 8.7 x 10-1
  2. 225,000 / 75 =
  3. 2.3x10-2 x 4.5x10-5 =
  4. 3.4x1023 / 42.1 =
  5. 5.6 x10-12 x 5.51x103 =
  6. 1.6x10-7 + 7.13x10-8
  1. Write the meaning (as a power of 10) for each of the following metric prefixes:

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a.kilo

b.centi

c.milli

d.micro

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  1. Give the metric prefix that corresponds to each of the following meanings:

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  1. one million
  2. one tenth
  3. 10-2
  4. One thousandth

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SI Unit Conversions – Using Dimensional Analysis Technique

  1. 0.032 g to milligrams
  1. 7.3 x 10-3 km to meters
  1. 4.7 nm to meters
  1. 0.072 m to centimeters
  1. 8.34 x 106 s to kiloseconds
  1. 6.7 ms to seconds
  1. 45.3 kcal to calories
  1. 0.57 μg to centigrams
  1. 0.0023 km to decimeters
  1. Balance this equation: solutions of sodium chlorate and barium nitrate react to form barium chlorate and sodium nitrate.
  1. 678 cg to kilograms
  1. 5.75 x 105 cm3 to liters (recall that 1 cm3= 1 mL)
  1. Convert 8.34x106 sec to ksec.
  2. Convert 7.62 x 103 mL to cL.
  3. Convert 950 g to kg.
  4. Convert 73.5 km/hr to m/s.
  1. Convert 4.52 g/mL to kg/L.
  1. Predict the products and balance a single replacement reaction between potassium and titanium (IV) oxide.

  1. How many inches are in 1.0 millimeter (use 1 inch = 2.54 cm)?
  1. How many mg in 1.40 lb (where 1.0kg = 2.2 lb)?
  1. How many cm3 in 3.45 L?

************ADD MORE Basic DA problems on this page for next year. Need more practice before moving on to tougher ones. (or just spread out)

  1. a) The distance from the moon to the earth is 384,400. km. How many miles is this?

b)Light travels at 186,000 miles per second. How many minutes does it take light to reach us from the moon?

  1. An average human lives to be 70.0 years old. How many seconds would have elapsed during this human’s lifetime?
  1. A copper (II) chloride solution has a concentration of 8.43g per liter. How many mg of copper (II) chloride are contained in 6.12mL of this solution?
  1. A particle of gas is moving at 45.8 m/s. It hits one wall of a container, bounces off, and hits the other wall 25 cm away. How long did it take for the gas particle to go from one wall to another?
  1. A sample of seawater contains 6.277 g sodium chloride per liter of solution. How many mg of salt would be found in 15.0 mL of seawater?
  1. The density of iron is 7.86 g/mL. What volume of iron (in liters) will have a mass of 250.0 g?
  1. Sound travels at approximately 1200 km/hr. How far away (in meters) is a lightning strike if you hear thunder in 11.5 seconds?
  1. Balance this synthesis equation: barium and oxygen react to form barium oxide.

Moles!

  1. How many molecules are in the quantities below? (use 6.022 x 1023 mlc/mol)

Example: 3.50 moles x 6.022 x 1023 mlc/mol = 2.11 x1024 molecules

  1. 2.0 moles
  1. 1.776 moles
  1. 0.732 moles
  1. How many moles are in the number of molecules or formula units below?

Example using “railroad track” approach:

4.284x1024 molecules / 1 mol / 7.11 moles
1 / 6.022 x 1023 mlc
  1. 1.204x1024 molecules
  1. 1.56x1020 formula units
  1. 3.425x1026 molecules
  1. What is the mass in grams of the following?
  2. 1 mol Ag
  3. 2.5 mol Fe
  4. 3.24 mol Cl
  5. Determine the number of moles in the following:
  6. 10.0 g Li
  7. 367 g Mg
  8. 72.1 g Si
  9. How many atoms of iron are in 15.89 moles of iron?
  1. How many moles of sodium chloride are in 7.51x1019 formula units of NaCl?
  1. What would be the mass of 5.34 moles of Vanadium?
  1. How many moles would 4.87 grams of fluorine be equal to?
  1. Determine the molar mass of each of the following compounds:
  1. Example: K2O K = 39.1g/mol x 2 = 78.2 g/mol

O = 16.0g/mol x 1 = 16.0 g/mol

Total= 94.2 g/mol

  1. KMnO4
  1. Na2SO4
  1. Calcium nitrate
  1. Aluminum sulfate
  1. Ammonium phosphate
  1. Iron(III) sulfite
  1. Copper(II) sulfate pentahydrate = CuSO4.5H2O
  1. Mg3(PO4)2
  1. H2CO3
  1. Hg2Cr2O7
  1. Ba(ClO3)2
  1. What is the mass of each of the following? (hint: determine molar mass first)
  2. 2.54 moles of NaCl
  1. 0.500 moles of H2SO4
  1. 1.706 moles of KMnO4
  1. 3.211 moles of CuSO4·5H2O
  1. How many moles are in the quantities below?
  2. 25.0 g of NaCl
  1. 125 g of H2SO4
  1. 105.98 g of KMnO4
  1. 72.5 g of KCl
  1. How many grams are in 2.4 moles of sulfur?
  1. How many grams are in 3.34 moles of potassium sulfide?
  1. How many moles are in 68.00 g of copper(II) hydroxide?
  1. How many formula units are in 68.00 g of copper(II) hydroxide?
  1. How many hydroxide ions are in 68.00 g of copper(II) hydroxide?
  1. How many copper ions are in 68.00 g of copper(II) hydroxide?
  1. How many molecules are there in 454 g of Na2SO4?
  1. How many grams are there in 2.32x1024 atoms of silver?
  1. How many grams and atoms are there in 5.67x1020 molecules of carbon dioxide (CO2)?
  1. How many grams are there in 7.34x1023 formula units of silver nitrate?
  1. How many silver ions are there in 7.34x1023 formula units of silver nitrate?
  1. How many sodium ions are there in 454 g of Na2SO4?
  1. How many molecules are in 62.17 g of sulfur dioxide (SO2)?
  1. How many atoms are in 62.17 g of sulfur dioxide?
  1. How many moles are in 1.23x1025 molecules of sodium chloride?
  1. How many grams of oxygen can be produced from 100.0 g of KClO3?
  1. Determine the percent composition of all elements in each of the following compounds:
  1. Ammonium sulfite – (NH4)2SO3example calculation:
  1. Aluminum acetate
  1. Sodium bromide
  1. Copper(II) hydroxide
  1. Magnesium carbonate
  1. Iron(II) phosphate
  1. Beryllium nitride
  1. Potassium cyanide
  1. Manganese(III) nitrate
  1. Nickel(III) sulfate
  1. Silver nitrate
  1. Copper(I) chloride
  1. Water
  1. What percentage of water is found in CuSO4·5H2O?
  1. What percentage of water is found in Na2S·9H2O?
  1. A 5.00 g sample of a hydrate of BaCl2 was heated, and only 4.35 g of the anhydrous salt remained. What percentage of water was in the hydrate?
  1. A 3.24 g sample of Na2CO3·H2O is heated to constant mass. How much (g) anhydrous salt remains?

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