Answer:
D
Explanation:
This is because, of chemical reaction
Moles of Oxygen= 2.8075 moles
<h3>Further explanation</h3>
Given
29.2 grams of acetylene
Required
moles of Oxygen
Solution
Reaction(Combustion of Acetylene) :
2 C₂H₂ (g) + 5 O₂ (g) ⇒ 4CO₂ (g) + 2H₂O (g)
Mol of Acetylene :
= mass : MW Acetylene
= 29.2 g : 26 g/mol
= 1.123
From equation, mol ratio of Acetylene(C₂H₂) : O₂ = 2 : 5, so mol O₂ :
= 5/2 x mol C₂H₂
= 5/2 x 1.123
= 2.8075 moles
1 mole=6.02 ×10
8.3 moles=?
8.3×6.02×10=499.66 molecules
therefore ghe no. of molecules = 499.66
Answer:
0.2g
Explanation:
All radiodecay follows the 1st order decay equation
A = A₀e^-kt
A => Activity at time (t)
A₀ => Initial Activity at time = 0
k => decay constant for isotope
T => time in units that match the decay constant
Half-Life Equation => kt(½) = 0.693 => k = 0.693/34 min = 0.0204min¹
A = A₀e^-kt = (26g)e^-(0.0204/min)(238min) = (26g)(0.0078) = 0.203g ~ 0.2g (1 sig fig).
