Explanation:
<u>Periodic table is the tabular display of elements that are arranged by the increasing atomic number.
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Structure of the periodic table shows various periodic trends.
<u>Significance:
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The periodic table is very important because it gives an organized way to provide lots of information about the elements and how they can be related to one another. The table gives a systematic approach to study the elements and their properties. The table can also be used to predict the properties of the elements which have not been discovered yet.
The question has missing information, the complete question is:
Cobalt(II) chloride forms several hydrates with the general formula CoCl₂.xH₂O, where x is an integer. If the hydrate is heated, the water can be driven off, leaving pure CoCl₂ behind. Suppose a sample of a certain hydrate is heated until all the water is removed, and it's found that the mass of the sample decreases by 22.0%. Which hydrate is it? That is, what is x?
Answer:
CoCl₂.26H₂O
Explanation:
The molar masses of the compounds that forms the hydrate are:
Co = 59 g/mol
Cl = 35.5 g/mol
H = 1 g/mol
O = 16 g/mol
The molar mass of CoCl₂ is 130 g/mol and of H₂O is 18 g/mol, thus for the hydrate, it will be 130 + 18x g/mol.
Let's suppose 1 mol of the compound. Thus, the mass of the hydrate is: 130 + 18x, and the mass of CoCl₂ will be 130 g. Because the mass decreassed by 22.0% :
0.22*(130 + 18x) = 130
130 + 18x = 590.91
18x = 460.91
x ≅ 26
Thus, the hydrate is CoCl₂.26H₂O
Answer:
The image shows that the red guards were a paramilitary group.
The image also shows that another role of the red guards was to adhere to maos teaching and impose them on the people
Explanation:
The correct answer is D because the the rest will have different answers depending on the person you ask. D can be proven with facts by research
Answer:
B) 52.000 amu.
Explanation:
- An element can have differing numbers of neutrons in its nucleus, but it always has the same number of protons. The versions of an element with different neutrons have different masses and are called isotopes.
- The average atomic mass for an element is calculated by summing the masses of the element’s isotopes, each multiplied by its natural abundance on Earth.
- Average atomic mass of P = ∑(Isotope mass)(its abundance)
<em>∴ Average atomic mass of Cr = (Cr-50 mass)(its abundance) + (Cr-52 mass)(its abundance) + (Cr-53 mass)(its abundance) + (Cr-54 mass)(its abundance) </em>
Abundance of isotope = % of the isotope / 100.
<em>∴ Average atomic mass of Cr =</em> (49.946 amu)(0.0435) + (51.941 amu)(0.8379) + (52.941 amu)(0.095) + (53.939 amu)(0.0236) = <em>52.000 amu.</em>
<em>So, the right choice is: </em><em>B) 52.000 amu.</em>
