<u>Answer:</u> The initial amount of Uranium-232 present is 11.3 grams.
<u>Explanation:</u>
All the radioactive reactions follows first order kinetics.
The equation used to calculate half life for first order kinetics:
We are given:
Putting values in above equation, we get:
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = 206.7 yrs
![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
= initial amount of the reactant = ?
[A] = amount left after decay process = 1.40 g
Putting values in above equation, we get:
![0.0101yr^{-1}=\frac{2.303}{206.7yrs}\log\frac{[A_o]}{1.40}](https://tex.z-dn.net/?f=0.0101yr%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7B206.7yrs%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B1.40%7D)
![[A_o]=11.3g](https://tex.z-dn.net/?f=%5BA_o%5D%3D11.3g)
Hence, the initial amount of Uranium-232 present is 11.3 grams.
1 litre of water is = 55.5 moles of water.
water is H2O
so, in water:
moles of oxygen = 55.5
moles of hydrogen = 2 x 55.5 = 111
Now, 1 mole each of <span>CH4, NH3, H2S, and CO2 are added:
For CH4:
moles of C = 1
moles of H = 4 x 1 = 4
For NH3:
moles of N = 1
moles of H = 3 x 1 = 3
For H2S:
moles of H = 2 x 1 = 2
</span>moles of S = 1
<span>
For CO2:
</span>moles of C = 1
moles of = 2 x 1 = 2
<span>
Now, add the total moles of each atom:
Hydrogen = 111 + 4 + 3 +1 = 119 moles
Oxygen = 55.5 + 2 = 57.5
Carbon = 1+1 = 2
Sulfur = 1
nitrogen = 1
</span>
Correct Question :
Mass of water = 50.003g
Temperature of water= 24.95C
Specific heat capacity for water = 4.184J/g C
Mass of metal = 63.546 g
Temperature of metal 99.95°C
Specific heat capacity for metal ?
Final temperature = 32.80°C
In an experiment to determine the specific heat of a metal student transferred a sample of the metal that was heated in boiling water into room temperature water in an insulated cup. The student recorded the temperature of the water after thermal equilibrium was reached. The data we shown in the table above. Based on the data, what is the calculated heat absorbed by the water reported with the appropriate number of significant figures?
Answer:
1642 J
Explanation:
Given:
Mass of water = 50.003g
Temperature of water= 24.95C
Specific heat capacity for water = 4.184J/g C
Mass of metal = 63.546 g
Temperature of metal 99.95°C
Specific heat capacity for metal ?
Final temperature = 32.80° C
To calculate the heat absorbed by water, Q, let's use the formula :
Q = ∆T * mass of water * specific heat
Where ∆T = 32.80°C - 24.95°C = 7.85°C
Therefore,
Q= 7.85 * 50.003 * 4.184
Q = 1642.32 J
≈ 1642 J
Answer:
g NaCl = 424.623 g
Explanation:
<em>C</em> NaCl = 3.140 m = 3.140 mol NaCl / Kg solvent
∴ solvent: H2O
∴ mass H2O = 2.314 Kg
mol NaCl:
⇒ mol NaCl = (3.140 mol NaCl/Kg H2O)×(2.314 Kg H2O) = 7.266 mol NaCl
∴ mm NaCl = 58.44 g/mol
⇒ g NaCl = (7.266 mol NaCl)×(58.44 g/mol) = 424.623 g NaCl
The number of tungsten Atoms in a typical light bulb filament is
5.76 × 
atoms of W
Explanation:
Write the given values of the problem
The diameter the tungsten wire in a light bulb filament Tungsten element W : molar mass = 183.84 g / mol
0.0176 g W × 
= 0.000096 mol W
0.000096 mol W × ![\frac{6.02 × [tex]10^{23 atoms}](https://tex.z-dn.net/?f=%5Cfrac%7B6.02%20%C3%97%20%5Btex%5D10%5E%7B23%20atoms%7D)
}{1 mol W}[/tex]
= 5.76 × atoms of W
