Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
The mass (in grams) of iron, Fe that can be made from 21.5 g of Fe₂O₃ is 15.04 g
We'll begin by writing the balanced equation for the reaction. This is given below:
2Fe₂O₃ -> 4Fe + 3O₂
- Molar mass of Fe₂O₃ = 159.7 g/mol
- Mass of Fe₂O₃ from the balanced equation = 2 × 159.7 = 319.4 g
- Molar mass of Fe = 55.85 g/mol
- Mass of Fe from the balanced equation = 4 × 55.85 = 223.4 g
From the balanced equation above,
319.4 g of Fe₂O₃ decomposed to produce 223.4 g of Fe
<h3>How to determine the mass of iron, Fe produced</h3>
From the balanced equation above,
319.4 g of Fe₂O₃ decomposed to produce 223.4 g of Fe
Therefore,
21.5 g of Fe₂O₃ will decompose to produce = (21.5 × 223.4) / 319.4 = 15.04 g of Fe
Thus, 15.04 g of Fe were produced.
Learn more about stoichiometry:
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It’s
1.A
2.C
3.B
hope it’s correct
Answer:
60 g/100 g water
Explanation:
Find 5 °C on the horizontal axis.
Draw a line vertically from that point until you reach the solubility curve for CaCl₂.
Then draw a horizontal line from there to the vertical axis.
The solubility of CaCl₂ is 60 g/100 g water.