The isotopes contribute to the average atomic mass based on their abundance. The result is that the "average" mass for the atoms of an element is dictated by the most abundant or common isotope. The average atomic mass for carbon is 12.0107 amu.
The atomic mass as displayed on the periodic table is a weighted average relative atomic mass of the naturally occuring isotopes of that element.
An isotope is an element with the same number of protons but a different number of neutrons
For example - Carbon naturally occurs in isotopes C12, C13 and C14 with abundances of 98.9% 1.1% and 'trace' respectively.
the average mass is then calculated by 12*98.9%+13*1.1% = 12.01g/mol
Answer:

Explanation:
Given that,
The length of a string, l = 0.87 m
Speed of the ball, v = 3.36 m/s
We need to find the acceleration of the ball. The acceleration acting on the ball is centripetal acceleration. It is given by :

So, the acceleration of the ball is
.
Temperature is a measure of the energy of molecules and energy is related to speed.
<span>The water in a pot is heated by convection. The water on the bottom will warm up and rise toward the surface and the cooler water will then sink to the bottom where it will be heated. </span>
<span>Oxygen will form ionic bonds with nitrogen. The others will not by themselves. </span>
<span>A high pH is indicative of a basic solution. HCl and H2SO4 are both strong acids and will result in a lower (more acidic) pH. Water is the standard. KOH is a strong base and will increase the pH. </span>
<span>An acidic solid will lower the pH of a solution. pH measures the number of hydrogen ions and a lower pH will mean that there are more H+ ions, but the solid could just have reacted with the OH- to cause the pH to decrease</span>
The type of reaction that occurred in the test tube is ACID BASE REACTION.
Acid base reaction is a type of chemical reaction in which an acid and a base react together to form salt and water molecules. It is also known as neutralization reaction. For the question given above, the applicable chemical reaction is as follows:
HF + NaOH = NaF + H2O
From this chemical reaction, it can be seen that, hydrogen fluoride, which is a weak acid react with sodium hydroxide which is a strong base to produce sodium fluoride, which is a salt and a molecule of water.