1) deep trenches
2) active volcanoes
3) arcs of islands along the tectonic boundaries
4) in some cases, mountain ranges
Charged particles or ionic particles?
Answer:
d. Radon-222
Explanation:
²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He
Alpha particle is a helium nucleus with mass number 4 and atomic number 2. According to the law of conversation of mass, the sum of the mass number and atomic number must be equal on both side of the reaction.
Since the mass number of Ra is 226 and that of He is 4. The mass number of the unknown element must be 226 - 4 = 222.
Since the atomic number of Ra is 88 and that of He is 2. The atomic number of the unknown element must be 88 - 2 = 86.
Now looking in the periodic table Radon is the only element with atomic number 86.
The answer is 42 grams of NaF are there in 1 mole.
<h3>
What is a mole ?</h3>
A mole is defined as 6.022 × 10²³ atoms, molecules, ions, or other chemical units.
and the molar mass of a substance is defined as the mass of 1 mole of that substance, expressed in grams per mole.
It is equal to the mass of 6.022 × 10²³ atoms, molecules, or formula units of that substance.
Molar Mass , i.e. mass of 1 mole of NaF is sum of molar mass of Na and F
23 + 19
42 grams
Therefore 42 grams of NaF Sodium-fluoride are there in 1 mole.
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Explanation:
Percentage Yield
= (3.37g/3.81g) * 100% = 88.45%.
Therefore 88.45% SO2 is the percentage yield.
