Question
help with #45
did i do #46 correct?
TI 211 213 300 C) 2940 mL 200 D) 41.6 mL E) 110. ml. 45. A sample of nitrogen gas had a volume of500. mL, essure in its closed container of 740 torr, and a temperature of 259C, what was the new volume of the gas when the temperature was changed to 50 oC and the new pressure was 760 torr, if the moles are constant? A) 530 mL VI B) 450 mL PIs auto tar C) 970 mL. 25 c D) 240 mL T E) 400 mL T2: 50" 213 46. At STP, how many moles of helium gas would occupy 1.00 L? O.Duu Imole the A) 2.24 moles 1.OO B) 224 moles 2.2.4 L C) 22.4 moles 0.446 moles E 0.0446 moles 47. What is the mass of neon that exerts a 720. mmHg,with a temperature of -15.0°C pressure of when the volume of the container is 760. mL? A) 0.0340 g B) 0.686 g C) 0.615 g D) 517 g
Explanation / Answer
45)
Vi = 500 mL
Pi = 740 torr
Ti = 25 oC = (25 + 273) K = 298 K
Pf = 760 torr
Tf = 50 oC = (50 + 273) K = 323 K
Vf = ?
use:
Pi*Vi/Ti = Pf*Vf/Tf
740*500/298 = 760*Vf/323
Vf = 528 mL
Answer: A
46)
at STP,
1 mol of gas occupies 22.4 L
So,
volume = number of mol * 22.4
1 L = n *22.4
n = 0.0446 mol
Answer: E