Answer:

Explanation:
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In this case, since these mole-mass relationships are understood in terms of the moles of the atoms forming the considered compound, we first realize that the chemical formula of the cobalt (III) nitrate is Co(NO₃)₃ whereas there is a 1:1 mole ratio of the cobalt (III) ion (molar mass = 58.93 g/mol) to the entire compound. In such a way, we first compute the moles of the salt (molar mass = 58.93 g/mol) and then apply the aforementioned mole ratio to obtain the grams of the required cation:

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The answer will be (4) HI because the greater the difference of the bonds in electronegativity, the more polar a bond is.
<u><em>on the basis of the reaction of heat in plastic , their are two types of plastics : </em></u>
<h2><u>
<em>Thermoplastic & Thermosetting plastics </em></u></h2>
<u><em>Thermoplastics : Plastics which easily get deformed (become soft )on heating and also get bend easily are known as thermoplastics . </em></u>
<u><em>examples : polythene , polyvinyl chloride and polystyrene .</em></u>
<u><em>thermosetting plastics : plastics which once moulded into a shape do not become soft on heating and cannot be moulded again are called thermosetting plastics .</em></u>
<u><em>examples : bakelite , melamine and formica</em></u>
The electronic configuration of x, y, and z.



<h3>What is an electronic configuration?</h3>
Electronic configuration, also called electronic structure, is the arrangement of electrons in energy levels around an atomic nucleus.
a.



b.
x= Period 1 and group18
Y=Element is in period 3 and Group 2
Z=Element is in period 3 and group 17.
c.
X, Y & Z represents Helium, magnesium, and chlorine.
Learn more about the electronic configuration here:
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Answer:
a) 7.0.
b) Nickel sulfate hepta hydrate.
c) 280.83 g/mol.
d) 44.9%.
Explanation:
<u><em>a) What is the formula of the hydrate?</em></u>
The mass of the hydrated sample (NiSO₄.xH₂O) = 5.0 g,
The mass of the anhydrous salt (NiSO₄) = 2.755 g,
The mass of water = 5.0 g - 2.755 g = 2.245 g.
∴ no. of moles of water = mass/molar mass = (2.245 g)/(18.0 g/mol) = 0.1247 mol.
∴ no. of moles of anhydrous salt (NiSO₄) = mass/molar mass = (2.755 g)/(154.75 g/mol) = 0.0178 mol.
∴ water of crystallization in the sample (x) = no. of moles of water/no. of moles of anhydrous salt (NiSO₄) = (0.1247 mol)/(0.0178 mol) = 7.0.
<u><em>b) What is the full chemical name for the hydrate?</em></u>
The name of the salt (NiSO₄.7H₂O) is Nickel sulfate hepta hydrate.
<u><em>c) What is the molar mass of the hydrate? </em></u>
(NiSO₄.7H₂O)
The molar mass = molar mass of NiSO₄ + 7(molar mass of H₂O) = (154.75 g/mol) + 7(18.0 g/mol) = 280.83 g/mol.
<em><u>d) What is the mass % of water in the hydrate?</u></em>
The mass % of water = (mass of water)/(mass of hydrated sample) x 100 = (2.245 g)/(5.0 g) x 100 = 44.9%.