Answer:
2.1
Explanation:
Calculation of moles of 
Mass of copper = 5.3 g
Molar mass of copper = 315.46 g/mol
The formula for the calculation of moles is shown below:
Thus,
Moles of = 0.0168 moles
According to the reaction,
1 mole of react with 1 mole of 
0.0168 moles of react with 0.0168 moles of
Moles of = 0.0168 moles
Molar mass of = 126.07 g/mol
Thus,
<u>Mass = Moles * Molar mass = 0.0168 moles * 126.07 g/mol = 2.1 g</u>
<u>Answer - 2.1</u>
<span>The correct answer should be two oxygen atoms. That's because it's properties are similar to carbon insofar that it can form four bonds, so if it forms bonds with 2 oxygen atoms then it will have all four bonds created since Oxygen forms double bonds. This would make SiO2 which is also known worldwide as silica.</span>
Answer:
Atomic mass = 127.198 amu
Explanation:
The average atomic mass is obtained by summing the masses of the isotopes each multiplied by its abundance.
Atomic mass = (97.62 * 0.0825) + (109.3 * 0.2671) + (138.3 * 0.6504)
Atomic mass = 8.05365 + 29.19403 + 89.95032
Atomic mass = 127.198 amu
The molarity is the number of moles in 1 L of the solution.
The mass of NH₃ given - 2.35 g
Molar mass of NH₃ - 17 g/mol
The number of NH₃ moles in 2.35 g - 2.35 g / 17 g/mol = 0.138 mol
The number of moles in 0.05 L solution - 0.138 mol
Therefore number of moles in 1 L - 0.138 mol / 0.05 L x 1L = 2.76 mol
Therefore molarity of NH₃ - 2.76 M
As he began to teach inorganic chemistry, Mendeleev could not find a textbook that met his needs. Since he had already published a textbook on organic chemistry in 1861 that had been awarded the prestigious Demidov Prize, he set out to write another one. The result was Osnovy khimii (1868–71; The Principles of Chemistry), which became a classic, running through many editions and many translations. When Mendeleev began to compose the chapter on the halogen elements (chlorine and its analogs) at the end of the first volume, he compared the properties of this group of elements to those of the group of alkali metals such as sodium. Within these two groups of dissimilar elements, he discovered similarities in the progression of atomic weights, and he wondered if other groups of elements exhibited similar properties. After studying the alkaline earths, Mendeleev established that the order of atomic weights could be used not only to arrange the elements within each group but also to arrange the groups themselves. Thus, in his effort to make sense of the extensive knowledge that already existed of the chemical and physical properties of the chemical elements and their compounds, Mendeleev discovered the periodic law.
