Bohrs model says that electrons move in fixed shells (which have fixed distances) around the nucleus of an atom.
150/30 = 5
HF1 20/2 = 10
HF2 10/2 = 5
HF3 5/2 = 2.5
HF4 2.5/2 = 1.25
HF5 1.25/2 = 0.625
Answer: 0.63g
Answer:
first one is a second one is e
Explanation:
Answer:
V = 81.14 L
Explanation:
Given data:
Volume of gas = ?
Number of moles = 3.30 mol
Temperature of gas = 25°C
Pressure of gas = 0.995 atm
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
25+273 = 298 K
now we will put the values in formula:
V = 3.30 mol 0.0821 atm.L/ mol.K 298 K / 0.995 atm
V = 80.74 L. atm / 0.995 atm
V = 81.14 L
Explanation:
A change that does not cause any change in chemical composition of a substance is known as a physical change.
For example, mass, density, volume etc are all physical changes.
On the other hand, a change that brings change in chemical composition of a substance is known as chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Hence, following statements are identified as chemical or physical changes as follows.
(a) Oxygen gas supports combustion : Chemical change
(b) Fertilizers help to increase agricultural production : Chemical change
(c) Water boils below
on top of a mountain : Physical change
(d) Lead is denser than aluminum : Physical change
(e) Uranium is a radioactive element : Chemical change