I looked up the half life for nickel-63 and then used the half life formula which is No=Nt*e^(kt) so the final answer is 20000 years for 26g of nickel-63 to decay to 6.5g
the dna is always held in the nucleus
Answer:
Explanation:
Equation of the reaction:
CaO(s) + 2H+(aq) -----> Ca2+(aq) + H2O(g)
The ∆Hrxn would be for one mole of CaO reacted or 2 moles of H+, whichever is the limiting reactant.
Number of moles = mass ÷ molar mass
Molar mass of CaO = 40 + 16
= 56 g/mol
moles of CaO = 2.90/56
= 0.0518 mol
Number of moles = concentration × volume
moles of HCl = 400 × 10^-3 × 1.500 = 0.6 moles
Moles of HCl = moles of H+
From the equation, 1 mole of CaO reacted with 2 moles of H+ to give 1 mole of water.
To find the limiting reagent,
0.6 mole of H+/2 moles of H+ × 1 mole of CaO
= 0.3 moles of CaO(> 0.0518 moles)
So, CaO is limiting reactant.
∆H = m × Cp × ∆T
m = density × volume
= 400 × 1
= 400 g
Cp = 4.184 J/g-ºC
∆T = +6 ºC
∆H = 400 × 4.184 × 6
= 10041.6 J
Since the reaction is exothermic,
∆Hrxn = -∆H/mol(CaO)
= -10041.6/0.0518
= -193853 J
= -193.9 kJ/mol.
If 28.0 grams of a gas occupies 22.4 liters at STP, the gas could be carbon monoxide, CO
<h3>Ideal gas </h3>
We understood from the ideal gas equation that 1 mole of any gas occupies 22.4 liters at standard temperature and pressure (STP)
<h3>How to determine the identity of the gas</h3>
To determine the identity of the gas, we shall determine the mass of 1 mole of each gas. This can be obtained as
For C₂H₂
1 mole of C₂H₂ = (12×2) + (2×1) = 26 g
For C₂H₆
1 mole of C₂H₆ = (12×2) + (6×1) = 30 g
For CO₂
1 mole of CO₂ = 12 + (16×2) = 44 g
For CO
I mole of CO = 12 + 16 = 28 g
From the above illustrations, we can see that 1 mole of CO is equivalent to 28 g.
Thus, the correct answer to the question is CO
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Option c. dendrochronology
tree rings or dendrochronology they allow to use it in calibration for carbon-14 on temporal placements of fragments of wood (from long dead trees).
Example Bristle cone pines (1957) 4723 years old