A balloon from the local store has a volume of 2.69 liters and an interal pressu
ID: 527166 • Letter: A
Question
A balloon from the local store has a volume of 2.69 liters and an interal pressure of 1.83 atmodpheres at 22 degree C. How many moles of gas does if contain? A) 2.72 B) 4.93 C) 0.203 D) 0.00549 One method us One method used to measure the volume of an irregularly shaped container is to all It with known mass of gas and measure the pressure and temperature of the gas. A mass of 3.679 grams of oxygen is added to the container at 372 degree C causing the container to develop a pressure of 493 ton. What is the volume of the container? A) 0.00595 liters B) 452 liters C) 0542 liters D) 150 liters The atomic masses of the elements are determined by A) adding the masses of the protons and neutrons in the nucleus. B) adding the masses of protons, neutrons and electrons. C) direct weighing of a sample of the element and determining the number of atoms. D) measuring the mass relative to the mass of an atom of 12C. Which of the following atoms is the largest? A) P B) Al C) K D) O Arrange the following in order of increasing second ionization energy. Ca, K, ALC, O A) AlExplanation / Answer
(1) (D) Mg and Sr because they belong to same group i.e 2nd group.
(2)
Molar mass of the given compound=2(Na)+1(N)+10(C)+8(O)+14(H)=2(23)+1(14)+10(12)+8(16)+14(1)=322 g/mol
Number of moles = mass / molar mass
2.496 = Mass / (322)
Mass of the given organic compound = 803.7 g.
(3) (C)
P V = n R T
n = 1.83 * 2.69 / (0.0821 * 295.15) = 0.210 mol
(4) (B)
Moles of Oxygen, n = mass / molar mass = 3.679 / 32 = 0.115 mol
Pressure, P = 493 torr = 493 / 760 atm = 0.649 atm
Temperature, T = 273.15 + 37.2 = 310.35 K
R = 0.0821 L.atm.K-1.mol-1
Volume, V = ?
V = n R T/ P
V = 0.115 * 0.0821 * 310.35 / 0.649
V = 4.55 L
(5)
(D)
(6)
(C) K belongs to 1st group.
(7)
(C) After losing one eletron K gets noble gas electronic configuration. Hence it requires highest energy to remove second eletron.
(8) (C) Li2Se
Li+ + Se2- ---------> Li2Se
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