Select the correct answer from each drop-down menu. Determine the molecular formula of the compound. A compound is used as a gasoline additive. It has a molecular weight of 60.10 atomic mass units and an empirical formula of [tex]$C _3 H _8 O$[/tex]. The molecular formula is C
Answer (2)
Calculate the empirical formula weight (EFW) of C 3 H 8 O : EF W = ( 3 × 12.01 ) + ( 8 × 1.008 ) + ( 1 × 16.00 ) = 60.094 amu .
Divide the molecular weight (MW) by the empirical formula weight (EFW) to find the ratio n: n = 60.094 60.10 ≈ 1 .
Multiply the subscripts in the empirical formula by n to obtain the molecular formula: ( C 3 H 8 O ) n = C 3 n H 8 n O n .
Since n = 1, the molecular formula is C 3 H 8 O .
Explanation
Problem Analysis We are given a compound used as a gasoline additive with a molecular weight of 60.10 atomic mass units. The empirical formula is given as C 3 H 8 O . Our goal is to determine the molecular formula of this compound.
Calculating Empirical Formula Weight First, we need to calculate the empirical formula weight (EFW) of C 3 H 8 O . The atomic weights are approximately: C = 12.01, H = 1.008, and O = 16.00. Therefore, the EFW is calculated as follows: EF W = ( 3 × 12.01 ) + ( 8 × 1.008 ) + ( 1 × 16.00 ) EF W = 36.03 + 8.064 + 16.00 EF W = 60.094 amu So, the empirical formula weight is approximately 60.094 atomic mass units.
Finding the Ratio n Next, we divide the molecular weight (MW) by the empirical formula weight (EFW) to find the ratio 'n': n = EF W M W = 60.094 60.10 ≈ 1.0001 Since 'n' must be an integer, we can round 1.0001 to 1.
Determining the Molecular Formula Now, we multiply the subscripts in the empirical formula by n to obtain the molecular formula: ( C 3 H 8 O ) n = C 3 n H 8 n O n Since n = 1, the molecular formula is C 3 H 8 O .
Final Answer Therefore, the molecular formula of the compound is C 3 H 8 O .
Examples
Understanding molecular formulas is crucial in various real-world applications. For instance, in the development of new drugs, chemists need to determine the exact molecular structure to ensure the drug interacts correctly with the body. Similarly, in environmental science, knowing the molecular formula of pollutants helps in understanding their behavior and designing effective remediation strategies. In the food industry, molecular formulas are essential for understanding the composition and nutritional value of different food products. For example, knowing the molecular formula of a gasoline additive helps engineers optimize engine performance and reduce emissions.
The molecular formula of the compound is C 3 H 8 O . This was determined by calculating the empirical formula weight and comparing it to the given molecular weight. Since the ratio of these weights is approximately 1, the molecular formula matches the empirical formula.
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