Answer:
i
Explanation:
Which of the following types of radiation from the Sun has the longest wavelength?
A) gamma
B) infrared
C) ultraviolet
D) visible
Answer:
B) infrared im pretty sure
Answer:
Infrared
Explanation:
PLSSS HELP. And there’s also at the bottom of the picture another option if u didn’t see it
Answer:
B. Gradualism
Explanation:
Plz help
I don't know chem that well
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]
A 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.
How many moles of methanol must be burned to release 1454 KJ of energy
Aqueous copper(II) sulfate solution is placed in an iron container and left to stand for several days. Which statement describes what happens? A) Atmospheric oxygen reacts with the copper(II) sulfate to give black copper(II) oxide. B) Some fine iron particles are formed in the solution. C )The part of the container in contact with the solution is coated with copper. D) The solution turns from green to blue.
Answer:
C )The part of the container in contact with the solution is coated with copper.
Explanation:
To understand the answer to the question, we must have a good knowledge of the electrochemical series.
Remember that iron is above copper in the electrochemical series. This means that iron can replace copper in an aqueous solution of a copper salt.
The following reaction occurs in the container;
Fe(s) + CuSO4(aq) -----> FeSO4(aq) + Cu(s)
This is why the part of the solution in contact with the container becomes coated with copper.
