Table of Contents
- 1 Why do equal amounts in moles of different elements and compounds have different masses even though they have the same number of particles?
- 2 What is 1 moles of a substance in grams equal to?
- 3 Why do moles of different substances have different masses?
- 4 Why does a similar mass of substances not necessarily mean a similar number of moles of a substance?
- 5 Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleus?
- 6 Why is nuclear density constant?
- 7 What is the mass of 1 mole of atoms in grams?
- 8 Is the number of nucleons equal to the mass of an isotope?
Why do equal amounts in moles of different elements and compounds have different masses even though they have the same number of particles?
Because atomic weights or masses of each atom of each element are proportional to each other, the same number of atoms of each element will give masses that are also proportional to each other.
What is 1 moles of a substance in grams equal to?
The mass of one mole of a substance is equal to that substance’s molecular weight. For example, the mean molecular weight of water is 18.015 atomic mass units (amu), so one mole of water weight 18.015 grams.
Why is the mass of a nucleus always less than the sum of the masses of its constituents?
In the case of nuclei, the binding energy is so great that it accounts for a significant amount of mass. The actual mass is always less than the sum of the individual masses of the constituent protons and neutrons because energy is removed when when the nucleus is formed.
Why is the mass of a nucleus slightly less than the mass of constituent nucleons?
During the formation of a nucleus, the protons and neutrons come closer to a distance of 10-14 m. The energy required for the purpose is spent by the nucleons at the expense of their masses. So mass of the nucleus found is less than the sum of the masses of the individual nucleons.
Why do moles of different substances have different masses?
The masses of 1 mole of different elements, however, are different, since the masses of the individual atoms are drastically different. The molar mass of an element (or compound) is the mass in grams of 1 mole of that substance, a property expressed in units of grams per mole (g/mol) (see Figure 1).
Why does a similar mass of substances not necessarily mean a similar number of moles of a substance?
Different substances have different molecular masses. Thus, equal masses have different numbers of atoms, molecules, or moles. On the other hand, equal numbers of moles of different substances have different masses.
How do you convert moles to grams in chemistry?
In order to convert the moles of a substance to grams, you will need to multiply the mole value of the substance by its molar mass.
What is equal to 1 mole of substance?
One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro’s number or Avogadro’s constant. The concept of the mole can be used to convert between mass and number of particles.. Created by Sal Khan.
Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleus?
Mass of an atomic nucleus is less than the sum of mass of the individual particles composing it.
Why is nuclear density constant?
This means that they are all about the same distance apart and since protons and neutrons have nearly identical mass then there will be the same mass for a given volume regardless of how many nucleons there are, hence the constant density.
Why equal masses of different substances do not contain equal numbers of molecules or moles?
[Since different substances usually do not have the same molar mass, one mole or Avogadro’s number of entities (molecules, etc.) will have different masses. Therefore, equal masses must contain different numbers of moles or molecules.]
How many nucleons are there in one mole of atoms?
The number of nucleons in one atom is almost the number of grams in one mole of atoms by definition. The definition of one mole is the number of C-12 that it takes to add up to 12 grams, exactly. There are 12 nucleons in C-12. So it’s by definition.
What is the mass of 1 mole of atoms in grams?
• The mass of an atom in amu is numerically the same as the mass of one mole of atoms of the element in grams. • One atom of sulfur has a mass of 32.07 amu; one mole of S atoms has a mass of 32.07 g. Mass of 1 H atom: 1.008 amu x 1.661 x10-24 g/amu = 1.674 x10-24 g Mass of 1 mole of H atoms: 1.674 x10-24g/H atom x 6.022 x1023H atoms = 1.008 g
Is the number of nucleons equal to the mass of an isotope?
The number of nucleons in the nucleus (protons and neutrons) is NOT equal to the mass in grams of 1 mole of that isotope. They may be close, but not the same. The mass number (nucleon number) is always a whole number (a counting number) because it represents the number of indivisible particles.
Why are moles measured by mass and not by number?
The same applies to molecules, ions and other particles. Because different individual particles have different weights. Even though moles are measured by mass, not by counting, a mole is a number. Would you expect a dozen marbles to weigh the same as a dozen cannonballs?