Answer: ₉₈²⁵³Cf
253 is a superscript to the left of the symbol, Cf, which represents the mass number, and 98 is a subscript to the left of the same symbol, which represents the atomic number.
Explanation:
1) The alpha decay equation shows that the isotope Fm - 257, whose nucleus has 100 protons and 157 neutrons, emitted an alpha particle (a nucleus with 2 protons and 2 neutrons).
2) Therefore:
i) the mass number decreased in 4, from 257 to 257 - 4 = 253.
2) the atomic number decreased in 2, from 100 to 100 - 2 = 98.
3) Hence the formed atom has atomic number 98, which is californium, Cf, and the isotope is californium - 253.
4) The item that completes the given alpha decay reaction is:
₉₈²⁵³ Cf.
5) The complete alfpha decay reaction is:
₁₀₀²⁵⁷ Fm → ₉₈²⁵³Cf + ₂⁴He
You can verify the mass balance:
257 = 253 + 4, and
100 = 98 + 2
Answer:
you tilt the cylinder at a slight angle so that the metal slides down the sides, rather than drops all it`s weight to the bottom
Answer:
Ka = 6.02x10⁻⁶
Explanation:
The equilibrium that takes place is:
We <u>calculate [H⁺] from the pH</u>:
- [H⁺] =
Keep in mind that [H⁺]=[A⁻].
As for [HA], we know the acid is 0.66% dissociated, in other words:
We <u>calculate [HA]</u>:
Finally we <u>calculate the Ka</u>:
- Ka =
![\frac{[9.12x10^{-4}]*[9.12x10^{-4}]}{[0.138]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5B9.12x10%5E%7B-4%7D%5D%2A%5B9.12x10%5E%7B-4%7D%5D%7D%7B%5B0.138%5D%7D)
= 6.02x10⁻⁶
