Answer:
8.3lb of fat were removed
Explanation:
To solve this problem we need to convert the liters of fat removed to mL. Using the mL and density we can find the grams. To convert grams to pounds we must use (1lb = 453.592g):
mL fat:
4.0L * (1000mL / 1L) = 4000mL
g fat:
4000mL * (0.94g / mL) = 3760g of fat
lb fat:
3760g of fat * (1lb / 453.592g) =
8.3lb of fat were removedA pan containing hot water is left on the counter and becomes cool mainly due to....
A. water molecules moving apart.
B. cold air penetrating the hot water.
C. heat from the water moving into the cooler air.
D. hot water reacting with the metal pan.
Answer:
C. heat from the water moving through the cooler air
I think it's C because when something cools down, it has to reach a point of thermal equilibrium with the matter (in this case air) around it. So heat transfer happens through convection from the heat in the pan to the cooler surrounding air. The heated air becomes less dense and rises, while cooler air, sinks to the surface of the water, gets heated, and rises. This convection cycle keeps happening until the water in the pan is around the same temperature with the air around it.
Radon-222 3.8 days
How many half lives have occurred if 12.5% of Rn-222 remains?
I need someone to explain how you do this to me?
3 half-lives have occured
Further explanationGiven
Half-life Radon-222 = 3.8 days
12.5% of Rn-222 remains
Required
Half-lives occurred
Solution
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
12.5% of Rn-222 remains ⇒ Nt/No = 0.125
Input the value :
[tex]\tt 0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\\\\t=11.4\rightarrow 3~half-lives[/tex]
