Answer:
the first one is protons and electrons the second one is protons the third one is neutrons and the forth one is also neutron
Answer:
Half-life = 3 minutes
Explanation:
Using the radioactive decay equation we can solve for reaction constant, k. And by using:
K = ln2 / Half-life
We can find half-life of polonium-218
Radioactive decay:
Ln[A] = -kt + ln [A]₀
Where:
[A] could be taken as mass of polonium after t time: 1.0mg
k is Reaction constant, our incognite
t are 12 min
[A]₀ initial amount of polonium-218: 16mg
Ln[A] = -kt + ln [A]₀
Ln[1.0mg] = -k*12min + ln [16mg]
-2.7726 = - k*12min
k = 0.231min⁻¹
Half-life = ln 2 / 0.231min⁻¹
<h3>Half-life = 3 minutes</h3>
Answer:- 2.92 kJ of heat is released.
Solution:- We have water at 100 degree C and it's going to be cool to 15 degree C.
So, change in temperature,
= 15 - 100 = -85 degree C
mass of water, m = 8.2 g
specific heat of water, c = 
The equation used for solving this type of problems is:

Let's plug in the values in the equation and solve it for q which is the heat energy:
q = (8.2)(4.184)(-85)
q = -2916.248 J
They want answer in kJ. So, let's convert J to kJ and for this we divide by 1000.

q = -2.92 kJ
Negative sign indicates the heat is released. So, in the above process of coiling of water, 2.92 kJ of heat is released.
<u>Q</u><u>U</u><u>E</u><u>S</u><u>T</u><u>I</u><u>O</u><u>N</u><u> </u><u>:</u>
- highest energy level for lithium
<u>A</u><u>N</u><u>S</u><u>W</u><u>E</u><u>R</u><u> </u><u>:</u>
- There are 2 electrons on the first energy level and 1 electron on the second. Explain that the first energy level can only have 2 electrons so the next electron in lithium is on the next (second) level. Explain that neon has 10 protons and 10 electrons.
Answer: The correct option is (c). The total pressure doubles.
Solution:
Initially, only 4 moles of oxygen gas were present in the flask.
(
) ( according to Dalton's law of partial pressure)
....(1)
= Total pressure when only oxygen gas was present.
Final total pressure when 4 moles of helium gas were added:

partial pressure of oxygen in the mixture :
Since, the number of moles of oxygen remains the same, the partial pressure of oxygen will also remain the same in the mixture.

= Total pressure of the mixture.
from (1)

On rearranging, we get:

The new total pressure will be twice of initial total pressure.