Chapter 13 Review

Use the relationship between pressure, temperature, and volume to answer questions Pressure increases then volume decreases – temperature is constant Pressure decreases then volume increases – temperature is constant Volume increases then temperature increases – pressure is constant Volume decreases when temperature decreases – pressure is constant

Find the density of 1.0 L of nitrogen at STP (d = PM/RT) d = (1atm)(28 g/mol) (.0821 atm g/mol K)(273 K) Answer: 1.24 g/L

Find the density of methane CH 4 at a pressure of 115 kPa and 45°C. (d=PM/RT) Need to change kPa to atm first 115 kPa x 1atm = 1.13 atm d = PM/RT d= (1.13 atm) (16 g) (.0821)(318K) Remember to change temperature to Kelvins

An 0.15 cm 3 oxygen bubble is released from a diver at a pressure of 186 kPa and a temperature of 6°C. What volume will this bubble have at the surface where the temperature is 13°C and a pressure of 1 atm? Combine both Charles and Boyle’s Laws and change kPa to atm because units of atm must be the same 186 kPa x 1atm P 1 V 1 = P 2 V 2 (1.84 atm)(.15 cm 3 ) = (1 atm) V T 1 T Answer:.26 cm 3

A helium balloon will burst above 4 Liters. If it is partially filled (3.4 L) at a temperature of 26°C. If pressure is constant, at what maximum temperature can the balloon be heated to before it bursts? V 1 = V 2 T 1 T L = 4L 299 T 2 Answer: Kelvins  78.8°C

Why would it be important for an anesthesiologist to know about gas laws to prevent injury to patients? Anesthesiologist needs to control temperature and pressure to not hurt or kill the patient

The barometer reads 756 mmHg, what is the atmospheric pressure in kPa? 756 mmHg x 1atm x kPa 760 mmHg 1 atm Answer: kPa

Cylinder of nitrogen gas is left in the sun; the temperature reaches 53°C. The cylinder has a volume of 15-L and contains 158 g of nitrogen. What is the pressure in atmospheres inside the cylinder? PV = nRT n = m/M Combine both equations to get PV = mRT M P(15) = 158g(.0821)(326) =10.01 atm 28 g/mol

Gas manometer has a pressure of 745 mmHg. Height of mercury is 9 mmHg higher on open end, what is the atmospheric pressure in atm? 745 mmHg – 9 mmHg = 736 mmHg 736 mmHg x 1 atm 760 mmHg Answer:.968 atm

Standard temperature 273 K

Standard pressure In atm = 1 atm In mmHg = 760 mmHg In Pa = Pa In kPa = kPa

One mole of gas has a volume of ___ at STP 22.4 L

A rising barometer means that atmospheric pressure is increasing

A falling barometer means that atmospheric pressure is decreasing

Ideal gas constant has a value of _____ in atm.0821 atm-L/mol-K

Find the volume of gases at STP – gasses are given in grams Molar volume of any gas at STP is 22.4 L Methane CH 4 – 32 grams  32/16 = 2 x 22.4 L = 44.8 L 16 is the molar mass of methane Water vapor – 36 grams  36/18 = 2 x 22.4 L = 44.8 L 18 is the molar mass of water Neon – 50 grams  50/20 = 2.5 x 22.4 L = 56 L 20 is the molar mass of neon

Statements about ideal gas Molecules have elastic collisions Energy remains the same Has mass Exerts pressure

Ideal gas law cannot predict behavior of a real gas at Low temperatures and high pressure

Pressure Pressure = Force/area

Boyle’s Law At constant temperature, pressure and volume are inversely proportional

Charles Law At constant pressure, temperature and volume are directly proportional

To use a manometer you need to Measure the difference in height of two mercury columns

Relationship between volume and number of moles of a gas If volume increases so does the number of moles