<span>Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into an atom with a mass number that is reduced by four and an atomic number that is reduced by two.
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Answer:
A system absorbs more energy than it releases and has a positive AH
Explanation:
Answer:
Explanation:
Endothermic (endo = into + thermic = heat) means that heat energy is going into a system.
The products will have more energy than the reactants and ΔH will be positive.
A is wrong, because ΔH is positive.
C and D are wrong, because the system absorbs more energy than it releases.
Answer:
The second option
Explanation:
Check
2×2Fe = 4Fe. Both sides have 4 Fe's
2x3 O = 3x2 O Both sides have 6 O's
3x1C = 3 C Both sides have 3 C's
Answer is: 7,826 kg of cryolite.
Chemical reaction: Al₂O₃ + 6NaOH + 12HF → 2Na₃AlF₆ + 9H₂<span>O.
m(</span>Al₂O₃) = 12,1 kg = 12100 g.
n(Al₂O₃) = m(Al₂O₃) ÷ M(Al₂O₃).
n(Al₂O₃) = 12100 g ÷ 101,96 g/mol = 111,86 mol; limiting reactant.
m(NaOH) = 60,4 kg = 60400 g.
n(NaOH) = 60400 g ÷ 40 g/mol.
n(NaOH) = 1510 mol.
m(HF) = 60,4 kg = 60400 g.
n(HF) = 60400 g ÷ 20 g/mol = 3020 mol.
From chemical reaction: n(Al₂O₃) : n(Na₃AlF₆) = 6 : 2.
n(Na₃AlF₆) = 2 ·111,86 mol ÷ 6 = 37,28 mol.
m(Na₃AlF₆) = 37,28 mol · 209,94 g/mol.
m(Na₃AlF₆) = 7826,56 g = 7,826 kg.