Answer : The correct option is (A).
Explanation :
- Endothermic reaction : When two liquids are combine into a flask, then the flask feels cold when we touch it because the system absorbed heat from the surrounding.
In general, endothermic process absorbs heat and cool the surrounding.
- Exothermic reaction : When two liquids are combine into a flask, then the flask feels hot when we touch it because the system released heat into the surrounding.
In general, exothermic process releases heat and rise the temperature of surrounding.
The answer to this questions is letterB
Answer:
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons. ... The value of the radius may depend on the atom's state and context.
Explanation:
Answer:
407pm is the edge length of the cubic unit cell
Explanation:
In a Face-centered cubic unit you can use Pythagoras theorem to relate edge length with atomic radius (As you can see in the picture), thus:
e²+e² = (4r)²
2e² = 16r²
e = √8 r
If the atomic radius of the atom is 144pm:
e = √8 ×144pm
e = 407ppm
407pm is the edge length of the cubic unit cell
Use the 1st order decay equation
<span><span>Cfinal</span>=<span>Cinitial</span><span>e<span>−kt</span></span></span>
by filling in and doing the math you will get:
<span> </span><span>Cfinal</span><span> = 1.11 grams Rn-222 after 23 days.
hope this helps
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