C5H11 Molecular Formula

University:
Campbell University
Course:
CHEM 111 | General Chemistry I
Academic year:

2021
Views:

388

Pages:

2
Author:

seburuk5q2

KEY Molecular Formula Name - ________________ 1.) A gas has the empirical formula CH2. If 0.850 of the gas at STP has a mass 1.59 , what is the molecular formula? . Answers - . × . = . .. . = = 2.99 ≈ 3 # $% . 2.) A gas has the percentage composition: 30.4% N and 69.6% O. If the density of the gas is 4.11 , at STP, what is the molecular formula of the gas? Answers – 30.4 . 3 * . 3 )× * . * = 2.17 ,- ) ./,0 . 2 = 1.00 ,- ) . × . = . 3 69.6 1× = 4.35 ,- 1 ./,0 1N : 2O = NO2 (E.F.) = 2.00 ,- 1 .% 2 %. 2 .. = .% %. = 2.00 ) 1 3.) A compound has an empirical formula C5H11. If 0.0275 ,- of the compound has a mass of 3.91 , what is the molecular formula of the compound? . Answers - .3 = . .. = . 3 . % = 1.99 ≈ 2 # $ 4.) When a sample of nickel carbonyl is heated, 0.0600 ,- of a gas containing carbon and oxygen is formed. The gas has a mass of 1.68 Answers – 42.9 #× . 3 * . 3 4 . 4 = 3.57 ,- # ./,0 = 1.00 ,- # .% .% and is 42.9% C. What is the molecular formula of the gas? = . . 3 2 . 3 57.1 1× .. = 3.57 ,- 1 ./,0 1C : 1O = CO (E.F.) = 1.00 ,- 1 2 %. 2 = . . = 1 #1 1 KEY 5.) A gas sample is analysed and found to contain 33.0% Si and 67.0% F. If the gas density is 7.60 at STP, what is the molecular formula of the gas? Answers – 33.0 56 × . 3 78 . 3 78 . 78 = 1.17 ,- 56 ./,0 . = 1 ,- 56 3.% × . 3 . = 67.0 9× . = 3.53 ,- 9 ./,0 1Si : 3F = SiF3 (E.F.) = 3 ,- 9 3. .. = 3. . = 2.0 56 9% 6.) A gas has the percentage composition: 78.3% B and 21.7% H. A sample bulb is filled with the unknown gas and weighed. The mass of unknown gas is found to be 0.986 /6,:0 the mass of a sample of nitrogen gas in the same bulb under the same conditions of temperature and pressure. What is the molecular formula of the unknown gas? Answers – 78.3 3. < 3. ;× < . < = 7.24 ,- ; ./,0 . = = 1 ,- ; 3.3 0.986 × 28.02 21.7 = $× . = 1B : 3H = BH3 (E.F.) = 2.97 ,- $ ) = 27.63 = 21.5 ,- $ ./,0 .. = 3.% . = 2.0 ; $% 7.) A gas has an empirical formula CH2. > 0.500 of the gas at STP has a mass of 0.938 , what is the molecular formula of the compound? Answers - . . × . = . .. = . . = 2.99 ≈ 3 # $% 8.) A sample of gas has an empirical formula of O and a molar mass which is 3 times that of CH4. What is the molecular formula of the gas? Answer - 3 × 16.05 #$ = 48.15 .. = . %. =3 1 2