To cut this short and for your understanding, ionic bond is formed between metals (mostly right column in periodic table). Covalent bond is formed between non-metals (mostly left column in periodic table). So polar covalent is also a covalent bond but it is polar, which means the shape of molecules are not symmetrical hence maybe an atom in a molecule has most of the electron attracted to it causing itself to be partial negative (since electron are negatively charged) and the other atom has its electron being attracted by others became partial positive. Polar covalent can also be when H atom is binding either to F, O or N (also known as hydrogen bond).
Answer:
a. 167 mL.
b. 39.3 %.
Explanation:
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In this case, for the undergoing chemical reaction, since 45.0 g of aluminum react, based on the 2:3 mole ratio with sulfuric acid, we can compute the required moles as shown below:

Next, since the molarity of a solution is computed based on the moles and volume (M=n/V), we can compute the required volume of sulfuric acid as shown below:

That in mL is 167 mL.
Moreover, for the percent yield, we compute the grams of aluminum sulfate that are produced based on the required 2.50 moles of sulfuric acid:

Therefore the percent yield is:

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Answer:
A neutral atom of Cobalt (Co) has an atomic number of 27 and an atomic mass of 59. Therefore, Co has 27 electrons, 27 protons and 32 neutrons.
Explanation:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
The atomic number Co is 27 it means it has 27 protons and 27 electrons.
The mass number is sum of protons and neutrons, thus number of neutrons are
59 - 27 = 32 neutrons
The empirical formula is Fe₃O₄.
The empirical formula is the <em>simplest whole-number ratio of atoms</em> in a compound.
The ratio of atoms is the same as the ratio of moles, so our job is to calculate the molar ratio of Fe to O.
I like to summarize the calculations in a table.
<u>Element</u> <u>Moles</u> <u>Ratio</u>¹ <u>×3</u>² <u>Integers</u>³
Fe 0.77 1 3 3
O 1.0 1.3 3.9 4
¹ To get the molar ratio, you divide each number of moles by the smallest number (0.77).
² If the ratio is not close to an integer, multiply by a number (in this case, 3) to get numbers that are close to integers.
³ Round off these numbers to integers (3 and 4).
The empirical formula is Fe₃O₄.