Number of moles of Hydrogen gas produced = 2.5 moles
Given the balanced chemical equation,

This means, 1 mole of Mg and 2 moles of HCl gives 1 mole of Hydrogen gas.
Given that 2.5 moles of Magnesium is taken and an excess of Hydrochloric acid.
The mole ratio of Magnesium and Hydrogen = 1:1
Thus 2.5 moles of Magnesium with an excess of Hydrochloric acid will yield 2.5 moles of Hydrogen gas.
[By referring excess of HCl, we may assume that it contains at least 5 moles of HCl. Then only 2.5 moles of Mg will produce 2.5 moles of Hydrogen gas].
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The first one is the answer
The number of protons never changes in an atom. More electrons means a negative charge and fewer means a positive charge. Once an atom has an electrical charge it is called an ion. In an ion the atomic number and atomic mass do not change from the original.
Answer:
19 g
Explanation:
Data Given:
Sodium Chloride (table salt) = 50 g
Amount of sodium (Na) = ?
Solution:
Molecular weight calculation:
NaCl = 23 + 35.5
NaCl = 58.5 g/mol
Mass contributed by Sodium = 23 g
calculate the mole percent composition of sodium (Na) in sodium Chloride.
Since the percentage of compound is 100
So,
Percent composition of sodium (Na) = 23 / 58.5 x 100
Percent of sodium (Na) = 39.3 %
It means that for ever gram of sodium chloride there is 0.393 g of Na is present.
So,
for the 50 grams of table salt (NaCl) the mass of Na will be
mass of sodium (Na) = 0.393 x 50 g
mass of sodium (Na) = 19 g