Concentration = 2.14 âś• 10-2 m
For [Br-], there are 2 ions so 2 x 2.14 x 10^-2 =4.28 x 10^-2
Ksp = [Pb][Br]^2 = 2.14 âś• 10-2 x (4.28 x 10^-2 )^2 = 39.20 x 10^-6
Ksp = 3.92 x 10^-5
Answer:
Explanation:
A radioactive isotope is an isotope that undergoes nuclear decay, breaking apart into a smaller nucleus and emitting radiation during the process.
The half-life of an isotope is the amount of time it takes for a certain quantity of a radioactive isotope to halve.
For a radioactive isotope, the amount of substance left after a certain time t is:
(1)
where
is the mass of the substance at time t = 0
m(t) is the mass of the substance at time t
is the half-life of the isotope
In this problem, the isotope is uranium-235, which has a half-life of
We also know that the amount of uranium left in the rock sample is 6.25% of its original value, this means that
Substituting into (1) and solving for t, we can find how much time has passed:
Answer:
Al₄O₅
Explanation:
The key at the bottom tells us the blue spheres are oxygen atoms and the red spheres are aluminum atoms. By counting, there are 4 aluminum atoms and 5 oxygen atoms. Therefore, the formula is Al₄O₅.
Answer:
16.2 J
Explanation:
Step 1: Given data
- Specific heat of liquid bromine (c): 0.226 J/g.K
- Volume of bromine (V): 10.0 mL
- Initial temperature: 25.00 °C
- Final temperature: 27.30 °C
- Density of bromine (ρ): 3.12 g/mL
Step 2: Calculate the mass of bromine
The density is equal to the mass divided by the volume.
ρ = m/V
m = ρ × V
m = 3.12 g/mL × 10.0 mL
m = 31.2 g
Step 3: Calculate the change in the temperature (ΔT)
ΔT = 27.30 °C - 25.00 °C = 2.30 °C
The change in the temperature on the Celsius scale is equal to the change in the temperature on the Kelvin scale. Then, 2.30 °C = 2.30 K.
Step 4: Calculate the heat required (Q) to raise the temperature of the liquid bromine
We will use the following expression.
Q = c × m × ΔT
Q = 0.226 J/g.K × 31.2 g × 2.30 K
Q = 16.2 J
In a redox reaction electrons are lost and gained in equal numbers. The species that is oxidized gives electrons to the species that is reduced. I hope this helps. Let me know if anything is unclear.
