All atoms are of <u>neutral charge, with an equal amount of protons and electrons.</u>
The number of years required for 1/4 cobalt-60 to remain after decay is calculated as follows
after one half life 1/2 of the original mass isotope remains
after another half life 1/4 mass of original mass remains
therefore if one half life is 5.3 years then the years required
= 2 x 5.3years = 10.6 years
Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Explanation:
Temperature of Solid
Melting temperature of Solid 
Temperature of liquid 
Specific heats of solid ethanol = 0.97 J/gK
Specific heats of liquid ethanol = 2.3 J/gK
Heat required to melt the the 25 g solid
at 159 K
= 159 K - 138 K = 21 K

Heat required to melt and raise the temperature of
upto 223 K
= 223 K - 159 K = 64 K

Total heat to convert solid ethanol to liquid ethanol at given temperature :
(1kJ=1000J)
Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
<span>Solubility product constant (Ksp) is </span>applied to the saturated ionic solutions<span> which are in equilibrium with its
solid form. The solid is partially dissociated into its ions.</span><span>
For the BaF, the dissociation as follows;
BaF</span>₂(s) ⇄ Ba²⁺(aq)
+ 2F⁻(aq)
<span>
Hence,
Ksp = [Ba</span>²⁺(aq)] [F⁻(aq)]²
Answer:
A , B, C
Explanation: D is a Diamagnetic