D. The number of electrons equals the atomic number for a neutral element. Each number after the letter refers to the number of electrons in that shell. So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.
Answer:
A. Both freezing and melting are physical changes.
Explanation:
Even if you were to freeze water, the molecules are still water molecules, and vise versa with melting it.
Fossil fuels are buried geologic deposits of organic materials. They are made of decaying plants and animals that have been turned into to natural oil. A few examples of fossil fuels are coal and oil.
<u>Given:</u>
Moles of He = 15
Moles of N2 = 5
Pressure (P) = 1.01 atm
Temperature (T) = 300 K
<u>To determine:</u>
The volume (V) of the balloon
<u>Explanation:</u>
From the ideal gas law:
PV = nRT
where P = pressure of the gas
V = volume
n = number of moles of the gas
T = temperature
R = gas constant = 0.0821 L-atm/mol-K
In this case we have:-
n(total) = 15 + 5 = 20 moles
P = 1.01 atm and T = 300K
V = nRT/P = 20 moles * 0.0821 L-atm/mol-K * 300 K/1.01 atm = 487.7 L
Ans: Volume of the balloon is around 488 L
The atoms are constantly in motion
