Answer:
80g/mol is the molar mass of the metal
Explanation:
A divalent metal M reacts with HCl as follows:
M + 2HCl → MCl₂ + H₂
The excess of HCl is titrated with NaOH. Thus, we can solve the moles of HCl that reacts with the metal and the moles of the metal. As the atomic weight is the ratio between the mass and moles of the atom:
<em>Moles NaOH:</em>
0.0546L * (0.22mol / L) = 0.0120 moles NaOH = Moles HCl in excess
<em>For NaOH and HCl solutions, Normality is the same than molarity.</em>
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<em>Moles HCl added:</em>
0.100L * (1.28mol / L) = 0.128 moles HCl * (50mL / 200mL) = 0.032 moles
<em>Moles HCl in that react:</em>
0.032 moles - 0.012 moles = 0.020 moles HCl
<em>Moles M:</em>
0.020 moles HCl * (1mol M / 2 mol HCl) = 0.010 moles M
<em>Molar mass M:</em>
0.8g / 0.010mol =
<h3>80g/mol is the molar mass of the metal</h3>
The answer is C. Mass number = protons + neutrons
Since the reaction has one mole of reactants versus two moles of products, the reaction would have a decrease in entropy. One mole of gas exerts less pressure than two moles of gas, and therefore one mole of gas has more entropy than two moles of gas.
Hope this helps
Answer:
D
Explanation:
Oxygen is the 8th element in the periodic table. This means that oxygen has 8 protons and 8 electrons. In order to get the number of neutrons you take the atomic weight in this case 15.9999~16 and you subtract it by the number of protons (16-8).
