Accelerator mass spectrometry

The use of a combination of mass spectrometers and an accelerator to measure the natural abundances of very rare radioactive isotopes. These abundances are frequently lower than parts per trillion. The most important applications of accelerator mass spectrometry are in archeological and geophysical studies, as, for example, in radiocarbon dating by the counting of the rare carbon-14 (radiocarbon; 14C ) isotope.

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Atoms

ATOMS

Law of constant composition: This states that “A chemical compound (if pure) always contains the same elements combined together in the same proportion by mass regardless of bow the compound is prepared or from where it is obtained”.

Law of conservation of mass: This is defined as “In every chemical reaction, the total mass of the products is the…

ملخص الفصل الثالث :العلاقات الكمية الكيميائية من كتاب الكيمياء للعالم زومدال Chapter 3 notes: Stoichiometry , AP chemistry Zumdahl

ملخص الفصل الثالث :العلاقات الكمية الكيميائية من كتاب الكيمياء للعالم زومدال Chapter 2 notes: Stoichiometry , AP chemistry Zumdahl

الكيمياء العامة 1 ، الكيمياء العامة 101 ، General Chemistry

ملخص الفصل الأول :أساسيات الكيمياء للعالم زومدال Chapter 1 chemistry foundation Notes Zumdahl AP

ملخص الفصل الأول أساسيات الكيمياء للعالم زومدال Chapter 1 chemistry foundation Notes Zumdahl

الكيمياء العامة 1 ، الكيمياء العامة 101 ، General Chemistry

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Percentage Composition of Compounds

The percentage composition of a compound is the percent by mass of each element in the compound.

How do we calculate the percent composition? Here are the steps:

Calculate the molar mass of the compound.

2.Divide the molar mass of each element by the molar mass of the compound and multiply by 100%.

For example, here is how you calculate the percent by mass of…

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Molecular Mass of the Elements and compounds

Molar mass  means the mass of one mole. The molar mass concept can be applied to elements and to compounds. Molar mass is expressed in grams. For example, one mole of carbon has amass of 12 grams. Therefore, carbon’s molar mass is 12 grams. This is equivalent to the statement that 6. 02 x 1023 atoms of carbon have a mass of 12 grams. Consider this example: chemists know that…

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isotopes and isobars

Isotopes: Isotopes are atoms of the same element having the same atomic number but different atomic masses. Note that the difference in the masses of isotopes is due to the different number of neutrons in their nuclei. Isotopes have the same chemical properties . because they have the same number of electrons. Isotopes have different physical properties because they have different number of neutrons.

Isobars: Nuclei of atoms of…

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Atomic Number and Mass Number

Atomic Number: Atomic number of an element is equal to the number of protons present in the nucleus of an element.

Atomic number = number of protons in one atom of element.

Since the atom as a whole is neutral therefore atomic number is the same as the number of electrons around the nucleus of an atom. Atomic number of an element does not change during…

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Conservation of Mass and Atoms

The law of Conservation of Mass states that the mass of matter before and after a chemical change remains the same. The number of atoms also remains the same. The only thing that changes is the arrangement of the atoms.

For example, the mass of hydrogen and oxygen before they combine to make water is the same as the mass of the water that they form. Furthermore, the…

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