A reaction that absorbs energy from the surroundings is called
a) activated.
b) exothermic.
c) reversible.
d) endothermic.
d
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An egg, which for the purposes of this problem can be assumed to be a 5-cm-diameter sphere having the thermal properties of water, is initially at a temperature of 4°C. It is immersed in boiling water at 100°C for 15 min. The heat transfer coefficient from the water to the egg may be assumed to be 1700 W/(m2 K). What is the temperature of the egg center at the end of the cooking period?
GIVEN
An egg is immersed in boiling water
Initial temperature (To) = 4°C
Temperature of boiling water (T?) = 100°C
Time that the egg is in the water (t) = 15 min. = 900 s
The heat transfer coefficient (hc) = 1700 W/(m2 K)
FIND
The temperature of the egg center at the end of the cooking period
ASSUMPTIONS
The egg is a sphere of diameter (D) = 5 cm = 0.05 m
The egg has the thermal properties of water
SKETCH
A sticky hockey puck slides along a frictionless, horizontal ice surface at 75 m/s in the +x direction. It collides with a second sticky puck originally sliding at 25 m/s in the -y direction. They collide totally inelastically. If the first puck has a mass equal to half that of the second, what is the angle of their final velocity vector below the +x direction?
A. 9.5 degrees B. 42 degrees C. 34 degrees D. 49 degrees E. 37 degrees
A certain photon after being scattered from a free electron at rest moves at an angle of 120° with respect to the incident direction. If the wavelength of the incident photon is 0.591 nm, what is the wavelength of the scattered photon?
A) 0.380 nm B) 0 nm C) 0.550 nm D) 0.591 nm E) 0.595 nm
Like Olympus Mons, volcanoes on Venus
A) have been extinct for billions of years. B) are shield volcanoes. C) form where continental plates collide. D) only form at the equator. E) are much larger than typical volcanoes on Earth.