Answer:
Evolution in the broadest sense explains that what we see today is different from what existed in the past. Galaxies, stars, the solar system, and earth have changed through time, and so has life on earth.Something that happened in the past is thus not "off limits" for scientific study. Hypotheses can be made about such phenomena, and these hypotheses can be tested and can lead to solid conclusions. Furthermore, many key aspects of evolution occur in relatively short periods that can be observed directly—such as the evolution in bacteria of resistance to antibiotics.Laws, like facts and theories, can change with better data. But theories do not develop into laws with the accumulation of evidence. Rather, theories are the goal of science.
Explanation:
The chemical formula of nickel (ii) hypochlorite is Ni(CIO)2. Nickel (II) has a charge of +2 while (CIO-) which is a poly atomic ion of chlorine and oxygen has a charge of -1. After balancing the charge of nickel with that of CIO- you get the chemical formula as Ni(CIO)2.
Answer:
Magnesium has 2 valence electrons.
Explanation:
The atomic number of magnesium is 12. This means that it has 12 protons and 12 electrons. The first electron shell can hold 2 electrons, the second can hold 8, so the third will have 2 electrons. The outermost shell of the atom has two electrons. Therefore, magnesium has 2 valence electrons.
Answer:
Percent yield = 94.5%
Theoretical yield = 26.89 g
Explanation:
Given data:
Mass of copper = 12.5 g
Mass of copper chloride produced = 25.4 g
Theoretical yield = ?
Percent yield = ?
Solution:
Cu + Cl₂ → CuCl₂
Number of moles of Copper:
Number of moles = mass/ molar mass
Number of moles = 12.5 g/ 63.55 g/mol
Number of moles = 0.2 mol
Now we will compare the moles of copper with copper chloride.
Cu : CuCl₂
1 : 1
0.2 : 0.2
Theoretical yield:
Mass of copper chloride:
Mass = Number of moles × molar mass
Mass = 0.2 mol × 134.45 g/mol
Mass = 26.89 g
Percent yield:
Percent yield = Actual yield / theoretical yield × 100
Percent yield = 25.4 g/26.89 g × 100
Percent yield = 94.5%
The answer is B. molality
