Answer:
487.33 K.
Explanation:
- To calculate the no. of moles of a gas, we can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant.
T is the temperature of the gas in K.
- If n is constant, and have two different values of (P, V and T):
<em>P₁V₁T₂ = P₂V₂T₁</em>
<em></em>
P₁ = 5.4 atm, V₁ = 1.0 L, T₁ = 33°C + 273 = 306 K.
P₂ = 4.3 atm, V₂ = 2.0 L, T₂ =??? K.
<em>∴ T₂ = P₂V₂T₁/P₁V₁</em> = (4.3 atm)(2.0 L)(306 K)/(5.4 atm)(1.0 L) = <em>487.33 K.</em>
Answer:
Explanation:one is true because if it is positiveit would not be attracting it would be sepperating
Given, half life of a certain radioactive element = 800 years.
Amount of substance remaining at time t = 12.5%
Lets consider the initial amount of the radioactive substance = 100%
Using the half life equation:
A = A₀(1/2)^t/t₁/₂
where A₀ is the amount of radioactive substance at time zero and A is the amount of radioactive substance at time t, and t₁/₂ is the half-life of the radioactive substance.
Plugging the given data into the half life equation we have,
12.5 = 100 . (1/2)^t/800
12.5/100 = (1/2)^t/800
0.125 = (0.5)^t/800
(0.5)^3 = (0.5)^t/800
3 = t/800
t = 2400 years
Thus the object is 2400 years old.
This is seen in the first law of Thermodynamics stating that matter and energy cannot be destroyed nor created.
