Answer:
139 g of CaH₂ were needed in the reaction
Explanation:
Determine the reaction:
CaH₂ + 2H₂O → Ca(OH)₂ + 2H₂
1 mol of calcium hidride reacts with 2 moles of water to produce 1 mol of calcium hydroxide and 2 moles of hydrogen
Let's determine the moles of formed hydrogen by the Ideal Gases Law
P . V = n . R . T
P = 823 Torr . 1 atm/760 Torr = 1.08 atm
T = Absolute T° → T°C + 273 → 21°C + 273 = 294K
1.08 atm . 147 L = n . 0.082 . 294K
(1.08 atm . 147 L) / (0.082 . 294K) = n → 6.60 moles
Ratio is 2:1. We make a rule of three:
2 moles of H₂ came from 1 mol of hydride
Then 6.60 moles of H₂ must came from 3.30 moles of hydride (6.60 .1) /2
Let's convert the moles to mass → 3.30 mol . 42.08 g/ 1 mol =
138.8 g ≅ 139 g
Answer:
minimum energy
Explanation:
minimum energy means maximum stability
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You would weigh the zinc with a weight, Zinc is a mineral so wether it's a solid or a liquid you would measure it with a zinc.
Answer:
Mole fraction for C₂₂H₁₉Cl₂NO₃ = 0.0086
Explanation:
Mole fraction remains a sort of concentration. It indicates:
moles of solute / (moles of solute + moles of solvent)
Moles of solute / Total moles.
Solute: Cypermethrin → C₂₂H₁₉Cl₂NO₃
Solvent: Water (PM = 18g/mol)
We calculate moles from solvent: 1000g /18 g/mol = 55.5 moles
We calculate PM for C₂₂H₁₉Cl₂NO₃
12g/mol . 22 + 1g/mol . 19 + 35.45 g/mol . 2+ 14g/mol + 16g/mol . 3 = 416 g/m
Moles of solute: 200 g / 416g/mol = 0.481 moles
Total moles: 0.481 + 55.5 = 55.98 moles
Mole fraction for C₂₂H₁₉Cl₂NO₃ = 0.481 moles / 55.98 moles = 0.0086
The answer to this question would be: BaCl 2
Barium is an alkali metal with 56 atomic number. Barium located in the group 2 of the periodic table because it has 2 valence electrons. Chlorine is a nonmetal that has 1 valence electron. When react, it would need 2 chlorine for each barium as the valence electron of barium is twice the chlorine.