For the first question:
Valuable ore deposits and gem crystals are often associated
with igneous intrusions. So for this question the correct option is option “d”.
An example like the Pegmatite’s, which are a form of igneous intrusions, is
responsible for the creation of variety of gems like topaz and tourmaline.
For the second question:
For this specific question, option “c” seems to be the
correct option. Weathering, deposition, compaction, cementation are the
possible sequence that leads to the formation of sedimentary rocks.
The answer for the question is Na3PO4
Answer:
XeF₂
Explanation:
Let's call the compound as XeaFb, where a and b are the number of atoms of each element. In the beginning, the partial pressure of XeaFb was 16 torr. By Dalton's Law, the total pressure of a gas mixture is the sum of the partial pressures of the components, so:
pH₂ = 64 - 16 = 48 torr
The reaction that happened was:
XeaFb + (b/2)H₂ → aXe + bHF
The stoichiometry of the reaction is 1:b/2:a:b. If all the XeaFb reacts:
1 torr of XeaFb -------- b/2 torr of H₂
16 torr -------- x
By a simple direct three rule:
x = 16b/2 = 8b torr of H₂ reacts
1 torr of XeaFb -------- a torr of Xe
16 torr -------- x
x = 16a torr of Xe is formed
Thus, 8b + 16a = 32
b + 2a = 4
The empirical formula is the minimum integer number of the elements in the compound. So, let's suppose a = 1 because fluorine can do only one bond, thus it's unprovable that will be more than one Xe bonded with one F:
b + 2*1 = 4
b = 2
Thus, the empirical formula is XeF₂.
That's false. A melting point is hot/warm, while the freezing point is cold.