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13 Cards in this Set
- Front
- Back
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What is the percent composition of a compound?
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The relative amounts of the elements in a compound are expressed as the percent composition of the percent by mass of each element in the the compound.
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T/F The percent by mass of an element in a compound is the number of grams of the element divided by the mass in grams of the compound, multiplied by 100%
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How can you determine the percent by mass of an element in a compound if you know only the compounds' formula?
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The subscripts in the formula of the compound are used to calculate the mass of each element in a mole of that compound. The sum of these masses is the molar mass. Then % mass = (mass of element in 1mol compound / molar mass of compound) multiplied by 100%
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What is the word origin of empirical?
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It means from experience or coming from experimental data.
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How many grams of hydrogen are contained in a 100gram sample of propane if you also know that propane is 81.8% carbon and 18% hydrogen?
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You would take 100g multiplied 18gH/100g C3H6 and this would give 18gH.
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What is the empirical formula?
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This is the basic ratio which gives the lowest whole-number ration of the atoms of the elements in a compound.
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T/F An empirical formula may or may not be the same as a molecular formula.
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The empirical formula of a compound represents what?
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the smallest whole-number ratio of the atoms in the compound.
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What is the empirical formula of ethyne C2H2 and styrene C8H8?
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the ratio is 1 to 1 for both.
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T/F CO2 has the same molecular formula as the empirical formula.
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This is true. The ratio is 1 to 2.
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What is the relationship between molecular formula and empirical formula?
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The molecular formula of a compound is either the same as its experimentally determined empirical formula, or it is a simple whole-number multiple of its empirical formula.
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Which of the following molecular formulas are also empirical formulas?
a.) C5H10O5 b.) C6H12O2 c.) C55H72MbH4O5 d.) C12H17ON |
a.) and b.) can be reduced. So only c.) and d.) are the empirical forumulas.
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How do you determine the percent by mass of any element in a given compound?
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Divide the elements's mass by the massof the compound and multiply by 100%
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