16) Zn(s) +2 HCI(aq) H2(g) + ZnCl2(aq) 16 When 25.0 g of Zn reacts, how many L o

Question

16) Zn(s) +2 HCI(aq) H2(g) + ZnCl2(aq) 16 When 25.0 g of Zn reacts, how many L of H2 gas are s, how many L of H2 gas are formed at 25 'C and a pressure of 854 mmg? B) 8.56 L A) 0.382L C 0.120 L D) 8.32 L E) 22.4L 17) As the temperature of a gas increases the density of the gas will A) depend on whther a catalyst is present O) remain constant B) decrease D) increase 18) Given the following reactions A+ B 2C AH = +100 kJ the enthalpy of reaction for 2C + A 2D is kJ. D)-300 E)-100 A) 400 B) 100 )300 19) According to kinetic-molecular theory, in which of the following gases will the average kinetic energy of the molecules be the highest at 200 C? A) Xe B) H2 C) Cl2 E) None. The molecules of all gases have the same average kinetic energy at any given temperature. 20) Ammonium nitrite undergoes thermal decomposition to produce only gases: 2H2O(g) NH4NO2 (s) N2 (g) + What volume (L) of N2 is produced by the decomposition of 35.0 g of NH4NO2 (s) at STP? (Molar Mass of NH4NO2 64.04 g) E) 47.3 D) 72.4 B) 24.8 C) 160. A) 12.2 21) A flask contains a mixture of He and Ne at a total pressure of 3.8 atm. There are 2.0 mol of He an C) 9.1 5.0 mol of Ne in the flask. The partial pressure of He is B) 1.86 , atm D) 0.74 E) 6.5 A) 1.09 22) Calcium hydride (CaH2) reacts with water to form hydrogen gas: CaH2 (s) + 2H20 (1) Ca(OH)2 (aq) + 2H2 (g) How many grams of CaH2 are needed to generate 66.7 L of H2 gas at a pressure of 0.888 atm ar temperature of 32°C? (Molar Mass of CaH2=4209 g) E) 70.5 D) 1.18 B) 49.8 99.6 A) 199

Explanation / Answer

Zn(s) + 2HCl(aq) -----------> H2(g) + ZnCl2(aq)
   1 mole of Zn react with HCl to gives 1 mole of H2
   65.4g of Zn react with HCl to gives 1 mole of H2
   25g of Zn react with HCl to gives = 1mole*25g/65.4g   = 0.387 moles of H2
PV = nRT
T = 25+273 = 298K
P = 854/760 = 1.124atm
V = nRT/P
    = 0.387*0.0821*298/1.124 = 8.32L
D. 8.32L
17.PM = dRT
   density inversley proportional to temperature.
B. decrease
18. A + B ------------> 2C     DH = 100KJ
     2D +B -------------> 2A     DH = -200KJ
------------------------------------------------------
    2D -----------------> 2C+ A DH = -100KJ
    2C + A -------------> 2D     DH = 100KJ
B. 100KJ
19.KE = 1/2mnC^2
   molar mass increases kinetic energy is increases.
   A. Xe
20. NH4NO2(s) -------------> N2(g) + 2H2O(g)
    1 mole of NH4NO2 to gives 1 mole of N2
    64.04g of NH4NO2 to gives 22.4L of N2
    35g of NH4NO2 to gives = 22.4L *35g/64.04   = 12.2L of N2
A. 12.2L
21.total no of moles = 2 + 5 = 7 moles
   mole fraction of He = 2/7 = 2=0.286
partial pressure of He = mole fraction of He * total pressure
                           = 0.286*3.8   1.09atm
A. 1.09atm
22. CaH2(s) + 2H2O(l) -------------> Ca(OH02 + 2H2(g)
    P = 0.888atm
    V = 66.7L
    T = 32+273 = 305K
    PV = nRT
     n   = PV/RT
         = 0.888*66.7/0.0821*305 = 2.36moles
2 moles of H2 obtained from 1 mole of CaH2
2.36 moles of H2 obtained from = 1*2.36/2 = 1.18 moles of CaH2
mass of CaH2 = no of moles * gram molar mass
               = 1.18*42 = 49.8g
B. 49.8g

   

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.