r speeE) 9) 9) Which one of the following gases wou owing gases would have the l
ID: 580970 • Letter: R
Question
r speeE) 9) 9) Which one of the following gases wou owing gases would have the lowest average molecular speed at 25°C? D) CH4 A) CO2 o2average B) SF6 is required to raise the D) 49 10) The specific heat capacity of lead i s 0.13 JWg-K. How much heat (in temperature of 25 g of lead from 22 C to 37°c? E) 5.8 x 10-4 A) 2.0 B) -0.13 C) 29 11), A r real gas will behave most like an ideal gas under conditions of A) low temperature and low pressure B) high temperature and low pressure C) high temperature and high pressure D) low temperature and high pressure E) STP of heat and that does 2500 J internal energy (AE) of a system that absorbs 7,655 J 12) The change in the of work on the surroundings is B) 5,155 A) 1.91 x 107 D) 10,155 E)-10,155 13 13) when a system ,aE is always positive. A) absorbs heat and has work done on it by the surroundings B) absorbs heat and does work on the surroundings C) gives off heat and has work done on it by the surroundings D) gives off heat and does work on the surroundings E) none of the above is always positive. 14) The value ofAH' for the following reaction is 328.3 kJ·The value of Arf for CaO(s) is kJ/mol CaCO3 (s) CaO (s) CO2 (g) Substance AHf (k/mol) CO (g) CO2 (8) -393.7 CaCO3 (s)-1207.0 -110.5 A) -485 B) -1600 C) -813.4 D) 813.4 E)-635.5
Explanation / Answer
9)
vrms = sqrt (3*R*T/M)
here : T is temperature in Kelvin
M is molar mass
vrms = sqrt (3*R*T/M)
here : T is temperature in Kelvin
M is molar mass
Since T is same for all, the one with lower molar mass will have higher speed
Lets list out molar mass of all given compounds
Molar mass of CO2 = 44.01
Molar mass of SF6 = 146.07
Molar mass of O2 = 32.0
Molar mass of CH4 = 16.042
Molar mass of N2 = 28.02
Increasing order of molar mass is:
CH4
N2
O2
CO2
SF6
Same is the order of decreasing vrms
From fastest to slowest
CH4
N2
O2
CO2
SF6
So, SSF6 is slowest
Answer: B
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