Given:
Half life(t^ 1/2) :30 years
A0( initial mass of the substance): 200 mg.
Now we know that
A= A0/ [2 ^ (t/√t)]
Where A is the mass that remains after t years.
A0 is the initial mass
t is the time
t^1/2 is the half life
Substituting the given values in the above equation we get
A= [200/ 2^(t/30) ] mg
Thus the mass remaining after t years is [200/ 2^(t/30) ] mg
Answer: The partial pressure of oxygen in the mixture is 321 mm Hg
Explanation:
According to Dalton's law, the total pressure is the sum of individual pressures.
Given : 
= total pressure of gases = 752 mm Hg
= partial pressure of Helium = 234 mm Hg
= partial pressure of nitrogen = 197 mm Hg
= partial pressure of oxygen = ?
Putting in the values we get:
The partial pressure of oxygen in the mixture is 321 mm Hg
B) Morrison and Franscioni's research done to create the Frisbee.
Answer:
- <u>1. Since the temperature of your body is higher than the temperature of the air and of the water, heat will flow from your body to the air and pool.</u>
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- <u>2. The pool feels cooler than air because the water can absorb heat energy faster than the air, due to liquids are better conductors than gases.</u>
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Explanation:
Heat always flows from warmer substances to colder ones.
The normal body temperature is 98ºF. Therefore, the heat will flow from your body to the air and pool, which are at a lower temperature of 80ºF. In both cases, you will lose thermal energy and the external parts of your body will cool down.
The difference between both cases is in the heat conduction capacity of both air and water.
Liquids (and solids) are better <em>thermal conductors </em>than gases because the conduction of heat occurs as result of the direct contact between the particles of matter: the atoms or molecules in hot matter vibrate faster than their neighbors and transmit them kinetic energy by direct contact.
Therefore, the liquid water in the swimming pool, at the same temperature than the air, will be able to absorb more heat in the same time from the body.
In conclusion, the body will cool down faster in water than in air which is why the pool feels cooler than air.
Ca=40.07841 ,Nitrogen=14.006722 ,Oxygen15.99943
molar mass= (1xMW of Ca)+(2xMWof N)+(6x MW of oxygen)
Molar mass (molecular weight) of Ca(NO3)2 is 164.0884 g/mol
