There are five hydrocarbon compounds (compounds of C and H) that have the formula C6H14. (These are isomers; they differ in the way that C and H atoms are attached. All are liquids at room temperature but have slightly different densities. Hydrocarbon to Density (g/mL) Hexane - 0.6600 g/mL 2,3-Dimethylbutane - 0.6616 g/mL 1-Methylpentane - 0.6532 g/mL 2,2-Dimethylbutane - 0.6485 g/mL 2-Methylpentane - 0.6645 g/mL (a) You have a pure sample of one of these hydrocarbons, and to identify it you decide to measure its density. You determine that a 5.0-mL sample (measured in a graduated cylinder) has a mass of 3.2745 g (measured on an analytical balance). Assume that the accuracy of the values for mass and volume is plus or minus one (±1) in the last significant figure. What is the density of the liquid? (b) Can you identify the unknown hydrocarbon based on your experiment? (c) You need a more accurate volume measurement to solve this problem, and you redetermine the volume to be 4.93 mL. Based on these new data, what is the unknown compound?
Question
There are five hydrocarbon compounds (compounds of C and H) that have the formula C6H14. (These are isomers; they differ in the way that C and H atoms are attached. All are liquids at room temperature but have slightly different densities.
Hydrocarbon to Density (g/mL) Hexane - 0.6600 g/mL 2,3-Dimethylbutane - 0.6616 g/mL 1-Methylpentane - 0.6532 g/mL 2,2-Dimethylbutane - 0.6485 g/mL 2-Methylpentane - 0.6645 g/mL
(a) You have a pure sample of one of these hydrocarbons, and to identify it you decide to measure its density. You determine that a 5.0-mL sample (measured in a graduated cylinder) has a mass of 3.2745 g (measured on an analytical balance). Assume that the accuracy of the values for mass and volume is plus or minus one (±1) in the last significant figure. What is the density of the liquid? (b) Can you identify the unknown hydrocarbon based on your experiment? (c) You need a more accurate volume measurement to solve this problem, and you redetermine the volume to be 4.93 mL. Based on these new data, what is the unknown compound?
Solution
(a) To calculate the density of the liquid, you would use the formula for density which is mass/volume. Given that the mass of the sample is 3.2745 g and the volume is 5.0 mL, the density would be calculated as follows:
Density = Mass/Volume = 3.2745 g / 5.0 mL = 0.6549 g/mL
(b) Based on the calculated density, it is difficult to definitively identify the unknown hydrocarbon. The calculated density is closest to that of 1-Methylpentane (0.6532 g/mL) and 2,2-Dimethylbutane (0.6485 g/mL), but the accuracy of the values for mass and volume is plus or minus one (±1) in the last significant figure. This means that the actual density of the sample could be slightly higher or lower than the calculated value, so it could potentially match any of the given hydrocarbons.
(c) If the volume is redetermined to be 4.93 mL, the density would be recalculated as follows:
Density = Mass/Volume = 3.2745 g / 4.93 mL = 0.6643 g/mL
Based on this new calculated density, the unknown hydrocarbon is most likely 2-Methylpentane, which has a given density of 0.6645 g/mL. This is the closest match to the recalculated density.
Similar Questions
The total number of structural isomers of molecular formula C6H14 is :A 4 B 5 C 6 D 7
Which alkane has the formula C2H6?MethaneEthanePropaneButane2Alkanes are ‘saturated’ hydrocarbons. What types of bonds do they contain?Double C=C bonds and single C-H bondsDouble C=C bonds and double C=H bondsSingle C-C bonds and single C-H bondsSingle C-C bonds and double C=H bonds3What is crude oil?Renewable fuel containing hydrocarbonsRenewable fuel containing minerals and metal oresNon-renewable fuel containing hydrocarbonsNon-renewable fuel containing minerals and metal ores 4What process is used to separate crude oil into simpler mixtures of hydrocarbons?Fractional distillationPolymerisationEvaporationFiltration5Which of the following statements about the process of fractional distillation is not correct? The temperature decreases going up the columnThe fractions collected at the top contain hydrocarbons with the longest moleculesCrude oil is fed in near the bottom of the column as hot vapourThe different fractions condense into liquids when they reach the temperature of their boiling points6Which of the following are some properties of small hydrocarbons compared with larger hydrocarbons? Higher boiling point, lower volatility, lower viscosity, lower flammabilityLower boiling point, higher volatility, lower viscosity, higher flammabilityHigher boiling point, higher volatility, higher viscosity, higher flammabilityLower boiling point, lower volatility, lower viscosity, lower flammability
Which of the following is the empirical formula for hexane, C6H14?
10)An unsaturated hydrocarbon weighing 1.68 gm has volume of 488 ml at S.T.P. If it contains 14% of hydrogen, then the family to which the hydrocarbon belongs is alkane alkene alkyl benzene
The molecular formula of octane is C8H18. Its empirical formula is C?H?. What number goes after the C?
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.