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t volume of nitrogen is heated from 10°C to 85°C·The initial pressure is 1.5 atm

ID: 1042806 • Letter: T

Question

t volume of nitrogen is heated from 10°C to 85°C·The initial pressure is 1.5 atm. What is the final pressure' T-10CH 273.0% 2896 TL: 2. A sample of 250 mL of NHs gas at 22 C is heated at constant pressure until it fills a volume of 500 mL. What is the new temperature in ?? v-2 Som 1 Vz-5 00ml 25oml 500 2.95 3. An unknown gas weighs 34.2 g and occupies 67 mL at 2.0 atnm and 245. °C What is its molecular weight? V-n /L: 134?2.ollur 34-2 66.6 m mo 4. An unknown gas has a volume of 200. L at 5 atm and -140°C. What is its volume ar STP? Explain what each of the following changes would do to the pressure in a closed container (increase or decrease pressure). 5. A) Part of the gas is removed dures Pressure B) The container size (volume) is decreasedrerpes Prassne C) Temperature is increased.

Explanation / Answer

1. initial                         final
    P1 = 1.5atm                    P2 =
    T1 = 10+273.15 = 283.15K      T2 = 85+273.15 = 358.15K
      P1/T1 = P2/T2
      P2    = P1T2/T1
            = 1.5*358.15/283.15   = 1.89atm

2. initial                       final
    V1 = 250ml                   V2 = 500ml
    T1 = 22+273.15 = 295.15K     T2 =
        V1/T1   = V2/T2
           T2    = V2T1/V1
                 = 500*295.15/250 = 590.3K
   new temperature = 590.3-273   = 317.3C^0
3. P = 2atm
   T = 24.5+273 = 297.5K
   V = 67ml = 0.067L
   PV = nRT
     n = PV/RT
        = 2*0.067/0.0821*297.5    = 0.00548moles
molar mass of unkown gas = mass of gas/no of moles
                          = 34.2/0.00548 = 6240.87g/mole
4. given conditions                        STP conditions
V1 = 200L                               V2 =
T1 = -140+273 = 133K                    T2 = 273K
P1 = 5atm                                P2 =1atm
           P1V1/T1   =   P2V2/T2
              V2      = P1V1T2/T1P2
                      = 5*200*273/133*1    = 2052.63L
5. A. pressure is decreses
   B. pressure is increases( P is inversely proportional to valume)
   C. pressure is increases( Pis directley porportianal ot T)