Answer:
We are heating the sample repeatedly to become a pure compound of only MgSO4 (withot H2O) and a constant mass.
Explanation:
Step 1: Data given
Mass of MgSO4·7H2O = 5.06 grams
The remaining MgSO4 had a constant mass of 2.47 grams.
Step 2: Explain why the sample in the crucible was heated repeatedly until the sample had a constant mass.
Before heating the compound has magnesium sulfate and water.
The total mass of this compound is 5.06 grams
By heating we try to eliminate the water.
After heating there remain mgSO4 with a mass of 2.47 grams
This means 5.06 - 2.47 = 2.59 grams is water. All of this is eliminated.
The heating process happens repeatedly to make sure the final compound is pure. So the 2.47 grams os only MgSO4. If the mass would not be constant. It means the compound is not pure, the not all the water is eliminated yet.
So we are heating the sample repeatedly to become a pure compound of only MgSO4 (withot H2O) and a constant mass.
<span>Let's assume
that the oxygen gas has ideal gas behavior.
Then we can use ideal gas formula,
PV = nRT</span>
Where, P is the pressure of the gas (Pa), V is the volume of the gas
(m³), n is the number of moles of gas (mol), R is the universal gas
constant ( 8.314 J mol⁻¹ K⁻¹) and T is temperature in Kelvin.
<span>
P = 2.2 atm = 222915 Pa
V = 21 L = 21 x 10</span>⁻³ m³
n = ?
R = 8.314 J mol⁻¹ K⁻¹
<span>
T = 87 °C = 360 K
By substitution,
</span>222915 Pa x 21 x 10⁻³ m³ = n x 8.314 J mol⁻¹ K⁻<span>¹ x 360 K
n
= 1.56</span><span> mol</span>
<span>
Hence, 1.56 moles of the oxygen gas are </span><span>
left for you to breath.</span><span>
</span>
I would say "Greek myths"
Answer:
Explanation:
A covalent bond involves the sharing of electrons to make the atoms more stable, and so they satisfy the Octet Rule (8 valence electrons).
Typically each atom contributes an electron to form an electron pair. This is a single bond. There are also double bonds (two pairs of electrons), triple bonds (three pairs of electrons), and coordinate covalent bonds.
Sometimes, to satisfy the Octet Rule and achieve stability, one atom contributes both of the electrons in an electron pair. This is different from other covalent bonds because usually each of the 2 atoms contributes an electron to make a pair.
The oxidation number of elements in equation below are,
4NH₃ + 3Ca(ClO)₂ → 2N₂ + 6H₂O + 3CaCl₂
O.N of N in NH₃ = -3
O.N of Ca in Ca(ClO)₂ and CaCl₂ = +2
O.N of N in N₂ = 0
O.N of Cl in Ca(ClO)₂ = +1
O.N of Cl in CaCl₂ = -1
Oxidation:
Oxidation number of Nitrogen is increasing from -3 (NH₃) to 0 (N₂).
Reduction:
Oxidation number of Cl is decreasing from +1 [Ca(ClO)₂] to -1 (CaCl₂).
Result:
<span>N is oxidized and Cl is reduced.</span>
