I believe the answer is A
Electrons can flow freely in metals.
Answer:
3.01 × 10^24 particles
Explanation:
According to Avagadro, in one mole of a substance, there are 6.02 × 10^23 atoms or particles.
Using the formula: N = n × NA
Where;
N= number of particles or atoms
n = number of moles
NA = Avagadro's constant or number
This means that for 5 moles of a substance, there will be:
5 × 6.02 × 10^23
= 30.1 × 10^23
= 3.01 × 10^24 particles
The answer to your question is a 12
Using the ideal gas law equation, we can find the number of H₂ moles produced.
PV = nRT
Where P - pressure - 0.811 atm x 101 325 Pa/atm = 82 175 Pa
V - volume - 58.0 x 10⁻³ m³
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 32 °C + 273 = 305 K
substituting these values in the equation,
82 175 Pa x 58.0 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 305 K
n = 1.88 mol
The balanced equation for the reaction is as follows;
CaH₂(s) + 2H₂O(l) --> Ca(OH)₂(aq) + 2H₂(g)
stoichiometry of CaH₂ to H₂ is 1:2
When 1.88 mol of H₂ is formed , number of CaH₂ moles reacted = 1.88/2 mol
therefore number of CaH₂ moles reacted = 0.94 mol
Mass of CaH₂ reacted - 0.94 mol x 42 g/mol = 39.48 g of CaH₂ are needed
