<< Chapter < Page Chapter >> Page >

(a) At what temperature does water boil at an altitude of 1500 m (about 5000 ft) on a day when atmospheric pressure is 8 . 59 × 10 4 N/m 2 ? size 12{8 "." "59" times "10" rSup { size 8{4} } " N/m" rSup { size 8{2} } ?} {} (b) What about at an altitude of 3000 m (about 10,000 ft) when atmospheric pressure is 7 . 00 × 10 4 N/m 2 ? size 12{7 "." "00" times "10" rSup { size 8{4} } " N/m" rSup { size 8{2} } ?} {}

Got questions? Get instant answers now!

What is the atmospheric pressure on top of Mt. Everest on a day when water boils there at a temperature of 70 . 0 º C? size 12{"70" "." 0°"C?"} {}

3 . 12 × 10 4 Pa size 12{ size 11{3 "." "12" times "10" rSup { size 8{4} } " Pa"}} {}

Got questions? Get instant answers now!

At a spot in the high Andes, water boils at 80 . 0 º C size 12{"80" "." 0°C} {} , greatly reducing the cooking speed of potatoes, for example. What is atmospheric pressure at this location?

Got questions? Get instant answers now!

What is the relative humidity on a 25 . 0 º C size 12{"25" "." 0°C} {} day when the air contains 18 . 0 g/m 3 size 12{"18" "." 0" g/m" rSup { size 8{3} } } {} of water vapor?

78.3%

Got questions? Get instant answers now!

What is the density of water vapor in g/m 3 size 12{"g/m" rSup { size 8{3} } } {} on a hot dry day in the desert when the temperature is 40 . 0 º C size 12{"40" "." 0°C} {} and the relative humidity is 6.00%?

Got questions? Get instant answers now!

A deep-sea diver should breathe a gas mixture that has the same oxygen partial pressure as at sea level, where dry air contains 20.9% oxygen and has a total pressure of 1 . 01 × 10 5 N/m 2 size 12{1 "." "01"´"10" rSup { size 8{5} } " N/m" rSup { size 8{2} } } {} . (a) What is the partial pressure of oxygen at sea level? (b) If the diver breathes a gas mixture at a pressure of 2 . 00 × 10 6 N/m 2 size 12{2 "." "00"´"10" rSup { size 8{6} } " N/m" rSup { size 8{2} } } {} , what percent oxygen should it be to have the same oxygen partial pressure as at sea level?

(a) 2 . 12 × 10 4 Pa size 12{ size 11{2 "." "12" times "10" rSup { size 8{4} } " Pa"}} {}

(b) 1 . 06 % size 12{ size 11{1 "." "06"%}} {}

Got questions? Get instant answers now!

The vapor pressure of water at 40 . 0 º C size 12{"40" "." 0°C} {} is 7 . 34 × 10 3 N/m 2 size 12{7 "." "34"´"10" rSup { size 8{3} } " N/m" rSup { size 8{2} } } {} . Using the ideal gas law, calculate the density of water vapor in g/m 3 size 12{"g/m" rSup { size 8{3} } } {} that creates a partial pressure equal to this vapor pressure. The result should be the same as the saturation vapor density at that temperature ( 51 . 1 g/m 3 ) . size 12{ \( "51" "." "1 g/m" rSup { size 8{3} } \) "." } {}

Got questions? Get instant answers now!

Air in human lungs has a temperature of 37 . 0 º C size 12{"37" "." 0°C} {} and a saturation vapor density of 44 . 0 g/m 3 size 12{"44" "." "0 g/m" rSup { size 8{3} } } {} . (a) If 2.00 L of air is exhaled and very dry air inhaled, what is the maximum loss of water vapor by the person? (b) Calculate the partial pressure of water vapor having this density, and compare it with the vapor pressure of 6 . 31 × 10 3 N/m 2 size 12{6 "." "31"´"10" rSup { size 8{3} } " N/m" rSup { size 8{2} } } {} .

(a) 8 . 80 × 10 2 g size 12{ size 11{8 "." "80" times "10" rSup { size 8{ - 2} } " g"}} {}

(b) 6 . 30 × 10 3 Pa size 12{ size 11{6 "." "30" times "10" rSup { size 8{3} } " Pa"}} {} ; the two values are nearly identical.

Got questions? Get instant answers now!

If the relative humidity is 90.0% on a muggy summer morning when the temperature is 20 . 0 º C size 12{"20" "." 0°C} {} , what will it be later in the day when the temperature is 30 . 0 º C size 12{"30" "." 0°C} {} , assuming the water vapor density remains constant?

Got questions? Get instant answers now!

Late on an autumn day, the relative humidity is 45.0% and the temperature is 20 . 0 º C size 12{"20" "." 0°C} {} . What will the relative humidity be that evening when the temperature has dropped to 10 . 0 º C size 12{"10" "." 0°C} {} , assuming constant water vapor density?

82.3%

Got questions? Get instant answers now!

Atmospheric pressure atop Mt. Everest is 3 . 30 × 10 4 N/m 2 size 12{3 "." "30"´"10" rSup { size 8{4} } " N/m" rSup { size 8{2} } } {} . (a) What is the partial pressure of oxygen there if it is 20.9% of the air? (b) What percent oxygen should a mountain climber breathe so that its partial pressure is the same as at sea level, where atmospheric pressure is 1 . 01 × 10 5 N/m 2 ? size 12{1 "." "01" times "10" rSup { size 8{5} } " N/m" rSup { size 8{2} } ?} {} (c) One of the most severe problems for those climbing very high mountains is the extreme drying of breathing passages. Why does this drying occur?

Got questions? Get instant answers now!

What is the dew point (the temperature at which 100% relative humidity would occur) on a day when relative humidity is 39.0% at a temperature of 20 . 0 º C size 12{"20" "." 0°C} {} ?

4 . 77 º C size 12{ size 11{4 "." "77"°C}} {}

Got questions? Get instant answers now!

On a certain day, the temperature is 25 . 0 º C size 12{"25" "." 0°C} {} and the relative humidity is 90.0%. How many grams of water must condense out of each cubic meter of air if the temperature falls to 15 . 0 º C size 12{"15" "." 0°C} {} ? Such a drop in temperature can, thus, produce heavy dew or fog.

Got questions? Get instant answers now!

Integrated Concepts

The boiling point of water increases with depth because pressure increases with depth. At what depth will fresh water have a boiling point of 150 º C size 12{"150"°C} {} , if the surface of the water is at sea level?

38 . 3 m size 12{ size 11{"38" "." 3``m}} {}

Got questions? Get instant answers now!

Integrated Concepts

(a) At what depth in fresh water is the critical pressure of water reached, given that the surface is at sea level? (b) At what temperature will this water boil? (c) Is a significantly higher temperature needed to boil water at a greater depth?

Got questions? Get instant answers now!

Integrated Concepts

To get an idea of the small effect that temperature has on Archimedes’ principle, calculate the fraction of a copper block’s weight that is supported by the buoyant force in 0 º C size 12{0°C} {} water and compare this fraction with the fraction supported in 95 . 0 º C size 12{"95" "." 0°C} {} water.

F B / w Cu F B / w Cu = 1 . 02 size 12{ { { left ( {F rSub { size 8{B} } } slash {w rSub { size 8{"Cu"} } } right )} over { left ( {F rSub { size 8{B} } } slash {w rSub { size 8{"Cu"} } } right ) rSup { size 8{′} } } } =1 "." "02"} {} . The buoyant force supports nearly the exact same amount of force on the copper block in both circumstances.

Got questions? Get instant answers now!

Integrated Concepts

If you want to cook in water at 150 º C size 12{"150"°C} {} , you need a pressure cooker that can withstand the necessary pressure. (a) What pressure is required for the boiling point of water to be this high? (b) If the lid of the pressure cooker is a disk 25.0 cm in diameter, what force must it be able to withstand at this pressure?

Got questions? Get instant answers now!

Unreasonable Results

(a) How many moles per cubic meter of an ideal gas are there at a pressure of 1 . 00 × 10 14 N/m 2 size 12{1 "." "00"´"10" rSup { size 8{"14"} } " N/m" rSup { size 8{2} } } {} and at 0 º C size 12{0°C} {} ? (b) What is unreasonable about this result? (c) Which premise or assumption is responsible?

(a) 4 . 41 × 10 10 mol/m 3 size 12{ size 11{4 "." "41" times "10" rSup { size 8{"10"} } `"mol/m" rSup { size 8{3} } }} {}

(b) It’s unreasonably large.

(c) At high pressures such as these, the ideal gas law can no longer be applied. As a result, unreasonable answers come up when it is used.

Got questions? Get instant answers now!

Unreasonable Results

(a) An automobile mechanic claims that an aluminum rod fits loosely into its hole on an aluminum engine block because the engine is hot and the rod is cold. If the hole is 10.0% bigger in diameter than the 22 . 0 º C size 12{"22" "." 0°C} {} rod, at what temperature will the rod be the same size as the hole? (b) What is unreasonable about this temperature? (c) Which premise is responsible?

Got questions? Get instant answers now!

Unreasonable Results

The temperature inside a supernova explosion is said to be 2 . 00 × 10 13 K size 12{2 "." "00"´"10" rSup { size 8{"13"} } " K"} {} . (a) What would the average velocity v rms size 12{v rSub { size 8{"rms"} } } {} of hydrogen atoms be? (b) What is unreasonable about this velocity? (c) Which premise or assumption is responsible?

(a) 7 . 03 × 10 8 m/s size 12{ size 11{7 "." "03" times "10" rSup { size 8{8} } `"m/s"}} {}

(b) The velocity is too high—it’s greater than the speed of light.

(c) The assumption that hydrogen inside a supernova behaves as an idea gas is responsible, because of the great temperature and density in the core of a star. Furthermore, when a velocity greater than the speed of light is obtained, classical physics must be replaced by relativity, a subject not yet covered.

Got questions? Get instant answers now!

Unreasonable Results

Suppose the relative humidity is 80% on a day when the temperature is 30 . 0 º C size 12{"30" "." 0°C} {} . (a) What will the relative humidity be if the air cools to 25 . 0 º C size 12{"25" "." 0°C} {} and the vapor density remains constant? (b) What is unreasonable about this result? (c) Which premise is responsible?

Got questions? Get instant answers now!

Questions & Answers

A soccer player kicked off a ball at velocity of 62 ft/s at angle 45°. A goal keeper is 43 yard away from the direction in which ball kicked off. At what minimum velocity he runs to meet the ball?
Ram Reply
A soccer player kicked off the ball at the velocity of 62 ft/s at 45° with horizontal.A goal keeper is 43 yard away from the ball kicked position.At what minimum velocity he runs to meet the ball?
Ram
what is torque
Deepak Reply
The turning effect of force is called torque.
Uzair
What is the effect of static electricity
Ruth
what there factors affect the surface tension of a liquid
Promise Reply
formula for impedance
muyiwa Reply
ehat is central forces
Nita Reply
what is distance?
Jonathan Reply
What does mean ohms law imply
Victoria Reply
ohms law state that the electricity passing through a metallic conductor is directly proportional to the potential difference across its end
muyiwa
what is matter
folajin Reply
Anything that occupies space
Kevin
Any thing that has weight and occupies space
Victoria
Anything which we can feel by any of our 5 sense organs
Suraj
Right
Roben
thanks
Suraj
what is a sulphate
Alo
any answers
Alo
the time rate of increase in velocity is called
Blessing Reply
acceleration
Emma
What is uniform velocity
Victoria
Greetings,users of that wonderful app.
Frank Reply
how to solve pressure?
Cruz Reply
how do we calculate weight and eara eg an elefant that weight 2000kg has four fits or legs search of surface eara is 0.1m2(1metre square) incontact with the ground=10m2(g =10m2)
Cruz
P=F/A
Mira
can someone derive the formula a little bit deeper?
Bern
what is coplanar force?
OLADITI Reply
forces acting and lying on d same plane
Promise
what is accuracy and precision
Peace Reply
How does a current follow?
Vineeta Reply
follow?
akif
which one dc or ac current.
akif
how does a current following?
Vineeta
?
akif
AC current
Vineeta
AC current follows due to changing electric field and magnetic field.
akif
you guys are just saying follow is flow not follow please
Abubakar
ok bro thanks
akif
flows
Abubakar
but i wanted to understand him/her in his own language
akif
but I think the statement is written in English not any other language
Abubakar
my mean that in which form he/she written this,will understand better in this form, i write.
akif
ok
Abubakar
ok thanks bro. my mistake
Vineeta
u are welcome
Abubakar
what is a semiconductor
Vineeta Reply
substances having lower forbidden gap between valence band and conduction band
akif
what is a conductor?
Vineeta
replace lower by higher only
akif
convert 56°c to kelvin
Abubakar
How does a current follow?
Vineeta
A semiconductor is any material whose conduction lies between that of a conductor and an insulator.
AKOWUAH
Practice Key Terms 4

Get the best College physics course in your pocket!





Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'College physics' conversation and receive update notifications?

Ask