A subduction zone<span> is a region of the Earth's crust where tectonic plates meet. Tectonic plates are massive pieces of the Earth's crust that interact with each other. The places where these plates meet are called plate boundaries.
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Answer:
Average atomic mass = 63.553 amu.
Explanation:
Given data:
Abundance of Y-63 = 69.17%
Abundance of Y-65 = 100 - 69.17 = 30.83%
Atomic mass of Y-63 = 62.940 amu
Atomic mass of Y-65 = 64.928 amu
Atomic mass of Y = ?
Solution:
Average atomic mass= (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass= (62.940×69.17)+(64.928×30.83) /100
Average atomic mass = 4353.560 + 2001.730 / 100
Average atomic mass = 6355.29 / 100
Average atomic mass = 63.553 amu.
Answer : Salt and Sand are weighed and kept in different 50 Milliliter beakers because, the experiment is about studying and separating the homogeneous mixture. As salt crystals are cubic and sand grains are rounded oblong grains. If we mix it together it would require a physical method to separate them. So, before starting the experiment it needs to be weighed in different beakers.
The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
Based on experiment 1:
Mass of Hg = 1.00 g
Mass of sulfide = 1.16 g
Mass of sulfur = 1.16 - 1.00 = 0.16 g
# moles of Hg = 1 g/200 gmol-1 = 0.005 moles
# moles of S = 0.16/32 gmol-1 = 0.005 moles
The Hg:S ratio is 1:1, hence the sulfide is HgS
Based on experiment 2:
Mass of Hg taken = 1.56 g
# moles of Hg = 1.56/200 = 0.0078
Mass of S taken = 1.02 g
# moles of S = 1.02/32 = 0.0319
Hence the limiting reagent is Hg
# moles of Hg reacted = # moles of HgS formed = 0.0078 moles
Molar mass of HgS = 232 g/mol
Therefore, mass of HgS formed = 0.0078 * 232 = 1.809 g = 1.81 g
