I WOULD SAY d. ALL OF ABOVE
Answer:
All of the above.
Explanation:
Gold is yellowish it is soft and malleable and also very dense.
Exothermic is a chemical reaction in which heat is released. Lighting a candle is an example of an exothermic because the flame is the heat being released.
Answer:
It is prepared small amounts of hydrogen cloride for uses in the lab.
It can be "generated in an HCl generator by dehydrating hydrochloric acid with either sulfuric acid or anhydrous calcium chloride."
Answer: It will take 11.775 seconds.
Explanation: As a sphere with a diameter of 0.1 mm, the area of an alveolus is
A = 4.π.r²
r for an alveolus would be: r = 0.00005m or r = 5.
m
Finding the area:
A = 4.3.14.(5.
)²
A = 3.14.
m²
The concentration change is to be 90% of the final, so
c = 0.9.3.14.
c = 28.26.
The oxygen diffusivity is 2.4.
m²/s, that means in 1 second 2.4.
of oxygen spread in one alveolus area. So:
1 second = 2.4.
m²
t seconds = 28.26.
m²
t = 
t = 11.775s
For a concentration change at the center to be 90%, it will take 11.775s.