Answer:
To monitor Pressure increase
Explanation:
the more pressure, the higher the production of the gas, which can be recorded, more pressure meaning higher production. Then vary the temperature.
There will be 7.5 g of Be-11 remaining after 28 s.
If 14 s = 1 half-life, 28 s = 2 half-lives.
After the first half-life, ½ of the Be-11 (15 g) will disappear, and 15 g will remain.
After the second half-life, ½ of the 15 g (7.5 g) will disappear, and 7.5 g will remain.
In symbols,
<em>N</em> = <em>N</em>₀(½)^<em>n</em>
where
<em>n</em> = the number of half-lives
<em>N</em>₀ = the original amount
<em>N</em> = the amount remaining after <em>n</em> half-lives
I think the answer is (1) Co. Because the element of Cobalt also has 2 electrons at the outer layer which is the same as Calcium. And the outer layer is an important factor which can affect the property of an element.
1. C : Mg(CN)2
2. B : N2O5
3. D : Ti(ClO4)3
4. A : Ni(NO3)3
5. D : Cobalt (III) Acetate
6. B : Nickel(II) sulfate
7. C : Dinitrogen Tetrafluoride
8. A : Phosphorus pentachloride<em />
9. C : Metallic <em>(<!> This is the only one I'm not 100% sure of)</em>
10. A : Ionic
11. C : Metallic
12. B : Covalent
