Answer:
the Rhyniognatha hirsti
Explanation:
at age 400 million years old
since the unit for the heat of fusion is kJ/mol, you're going to have to convert the grams into moles in order to cancel out the unit. After that, you can solve like normal.
Answer: increases by
As a chlorine atom becomes a negative ion, the atom "increases by" an electron
Explanation:
Chlorine atom has an atomic number of 17, and an electronic configuration of 1s2, 2s2 2p6, 3s2 3p5 showing 7 valence electrons in its outermost shell.
Hence, it receives a single electron to achieve a stable octet structure with electronic configuration of
1s2, 2s2 2p6, 3s2 3p6. Therefore, Cl- is a univalent negative ion with 8 valence electrons in its outermost shell. The increase is shown below
Cl + e- --> Cl-
Thus, as a chlorine atom becomes a negative ion, the atom "increases by" an electron
<h3>
Answer:</h3>
43.27 g Mg
<h3>
Explanation:</h3>
The balanced equation for the reaction between magnesium metal and hydrochloric acid is;
Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
From the equation;
1 mole of magnesium reacts with 2 moles of HCl
We are given;
3.56 moles of Mg and 3.56 moles of HCl
Using the mole ratio;
3.56 moles of Mg would react with 7.12 moles of HCl, and
3.56 moles of HCl would react with 1.78 moles of Mg
Therefore;
The amount of magnesium was in excess;
Moles of Mg left = 3.56 moles - 1.78 moles
= 1.78 moles
But; 1 mole of Mg = 24.305 g/mol
Therefore;
Mass of magnesium left = 1.78 moles × 24.305 g/mol
= 43.2629 g
= 43.27 g
Thus, the mass of magnesium that remained after the reaction is 43.27 g
