Hydrogen-1, Carbon-13, Nitrogen-15, Fluorine-19, and Phosphorus-31 are the most useful. Out of these, Hydrogen-1 and Carbon-13 in NMR are the most useful nuclei because the these atoms are the most commonly present in organic molecules.
Answer:
A decrease in temperature would decrease kinetic energy, therefore decreasing collisions possible.
Explanation:
A gas at a fixed volume is going to have collisions automatically. If you decrease the temperature (same thing as decreasing kinetic energy) you are cooling down the molecules in the container which gives them less energy and "relaxes" them. This decrease in energy causes them to move around much slower and causing less collisions, at a much slower rate. In a perfect world, these collisions do not slow down the molecule but we know that they do, just a very very small unmeasurable amount.
The number of moles present in 29.5 grams of argon is 0.74 mole.
The atomic mass of argon is given as;
Ar = 39.95 g/mole
The number of moles present in 29.5 grams of argon is calculated as follows;
39.95 g ------------------------------- 1 mole
29.5 g ------------------------------ ?

Thus, the number of moles present in 29.5 grams of argon is 0.74 mole.
<em>"Your question seems to be missing the correct symbol for the element" </em>
Argon = Ar
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Explanation:
The halogen family and noble gases are similar in just one particular way, they are groups of non-metals. All members of these two groups are categorized as non-metals.
Here are some of the differences between them;
- Halogens have 7 electrons in their outermost shell whereas noble gases have 8 electrons in theirs.
- Halogens are highly reactive elements, noble gases are non-reactive.
- Halogens are made up of electronegative elements where as noble gases are neither electropositive nor electronegative.