{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

q1w2.key

# q1w2.key - Dr Zellmer Time 23 mins Chemistry 122 Summer...

This preview shows pages 1–2. Sign up to view the full content.

Dr. Zellmer Chemistry 122 Wednesday 10:30 AM Time: 23 mins Summer Quarter 2008 June 25, 2008 Quiz I Name KEY Rec. Instr. 10:30 ---------------------------------------------------------------------------------------------------------------------------------------- 2 1. (5 pts) A sample of N gas occupies 10.00 L at 25°C and a pressure of 14.51 lb/in . At what 2 2 temperature (in °C ) will it occupy 20.00 L at a pressure of 0.9211 atm? (Mol. Wt.: N = 28.02) (1 atm = 101.325 kPa = 14.7 lb/in = 760 torr = 760 mm Hg) 2 Since P, V & T all change use the Combined Gas Law: 2 2 1 1 P V P V ------- = ------- T MUST be in kelvin 2 1 T T 1 1 1 P = 14.51 lb/in V = 10.00 L T = 25°C + 273.15 = 29 8 .15 K 2 14.7 lb/in 2 2 2 2 P = 0.9211 atm × ------------ = 13.5 4 0 lb/in V = 20.00 L T = ? 2 1atm 2 2 1 2 2 P V T P V 13.5 4 0 lb/in 20.00 L 2 2 1 T = ---------- = (-----)(-----)T = (----------------)(-----------) 29 8 .15 K = 55 6 .44 K = 28 3 .29°C 1 1 1 1 P V P V 14.51 lb/in 10.00 L 2 = 283°C (3 s.f.) 2. (7 pts) A gas with a molecular weight of 40.0 amu has a mass of 5.35 g at STP in a container of unknown volume. What is the volume (in L) of the container? STP => Standard Temp. & Pressure: T = 0°C (273.15K) & P = 1 atm To calculate the volume you need moles. You can get this from the molecular weight or molar mass, M , m mass m M = ---- = --------- or n = ----- (or use dimensional analysis) n moles M m 5.35 g 1 mol n = ---- = --------------- or ? mol = 5.35 g x --------- = 0.13 3 75 mol M 40.0 g/mol 40.0 g

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}