
<u>Difference </u><u>between </u><u>Atomic </u><u>mass</u><u>, </u><u>relative </u><u>atomic </u><u>mass </u><u>and </u><u>average </u><u>atomic </u><u>mass</u><u> </u><u>:</u><u>-</u>
<h3><u>Atomic </u><u>Mass </u><u>:</u><u>-</u></h3>
- Atomic mass is the mass of neutrons and protons present in the nucleus of an atom .
- It is always calculated for a single element and having direct value
- For isotopes also, the atomic mass is calculated separately . Example :- <u>Carbon </u><u>1</u><u>2</u><u> </u><u>,</u><u> </u><u>carbon </u><u>1</u><u>3</u><u> </u><u>and </u><u>carbon </u><u>1</u><u>4</u><u> </u><u>have </u><u>different </u><u>atomic </u><u>mass</u><u>. </u>
- The SI unit of Atomic mass is " u" and "amu"
<h3>
<u>Relative </u><u>Atomic </u><u>mass </u><u>:</u><u>-</u></h3>
- Relative atomic mass is mean mass of the atoms of an element which is compared to the 1/12th mass of carbon - 12 .
- Carbon - 12 is taken as a relative when we calculate the relative atomic mass of any element
- For calculating relative atomic mass, we need to know the masses, percentage and abundance of all types of elements
- Relative atomic mass is a dimension less quantity
<h3><u>Average </u><u>Atomic </u><u>Mass </u><u>:</u><u>-</u></h3>
- Average atomic mass is the average mass of an atoms of a particular element by considering it's isotopes
- While we calculate average atomic mass is a standardized number. Whereas, Average atomic mass sometimes varies geologically .
- It also includes percentage, abundance and masses of given element .
- In average atomic mass, We do not compare mean value with the 1/12 mass of carbon - 12
- The unit of Average atomic mass is "Amu" or " u " .
The answer for the following mention bellow.
- <u><em>Therefore the final temperature of the gas is 260 k</em></u>
Explanation:
Given:
Initial pressure (
) = 150.0 kPa
Final pressure (
) = 210.0 kPa
Initial volume (
) = 1.75 L
Final volume (
) = 1.30 L
Initial temperature (
) = -23°C = 250 k
To find:
Final temperature (
)
We know;
According to the ideal gas equation;
P × V = n × R ×T
where;
P represents the pressure of the gas
V represents the volume of the gas
n represents the no of moles of the gas
R represents the universal gas constant
T represents the temperature of the gas
We know;
= constant
×
= 
Where;
(
) represents the initial pressure of the gas
(
) represents the final pressure of the gas
(
) represents the initial volume of the gas
(
) represents the final volume of the gas
(
) represents the initial temperature of the gas
(
) represents the final temperature of the gas
So;
= 
(
) =260 k
<u><em>Therefore the final temperature of the gas is 260 k</em></u>
<u><em></em></u>
Answer:
It will take 5492 seconds to electroplate 0.5 mm of gold on an object .
Explanation:
Mass of gold = m
Volume of gold = v
Surface area on which gold is plated = 
Thickness of the gold plating = h = 0.5 mm = 0.05 cm
1 mm = 0.1 cm

Density of the gold = 

Moles of gold = 

According to reaction, 1 mole of gold required 3 moles of electrons,then 0.152 moles of gold will require :
of electrons
Number of electrons = N =
Charge on single electron = 
Total charge required = Q

Amount of current passes = I = 8 Ampere
Duration of time = T



It will take 5492 seconds to electroplate 0.5 mm of gold on an object .
The first thing we need to do here is to recognize the unit of molarity and the units of the given percentage of nitric acid.
Molarity is mol HNO3 / L of solution. This is our aim
The given percentage is 0.68 g HNO3/ g solution
multiplying this with density to convert g solution into mL solution and dividing with the molecular weight of HNO3 (63 g/mol) to convert g HNO3 to mol. Therefore we obtain
0.016 mol/ mL or 16.23 mol/ L (M)
B, E, F have 3 significant figures