Ionic bond is formed by two opposite type of substances (metal and non-metal) while both covalent or metallic bond is formed by two same type of substances (non-metal and non-metal form covalent bond, metal and metal form metallic bond). Idk if it's true or not.
Answer:- 9.4 minutes.
Solution:- Radioactive decay obeys first order reaction kinetics and the equation used to solve this type of problems is:

where, k is decay constant and t is the time.
is the initial amount of the radioactive substance and N is the remaining amount.
Since the value of decay constant is not given, so we need to calculate it first from given half life by using the formula:

where
stands for half life.
Given half life is 3.0 minutes.
So, 

Let's plug in the values in the first order reaction equation and solve it for t.

It could also be written as:



k = 9.4 min
So, the radioactive substance would take 9.4 minutes to decay from 40.0 grams to 4.5 grams.
Answer:J.J. Thomson, he was using a high-vacuum cathode-ray tube
Explanation:(I Googled it)
Answer:
<em>The grams of hydrogen gas that are released is 0.343 gram</em>
Explanation:
<em>Given that:</em>
<em>2 Na + 2h₂0 ⇒ 2Na0H +N₂</em>
<em>Molecules of Na = 7.9/2.3 = 0.343 mol Na</em>
<em>Now,</em>
<em>2 molecules of Na produces one mole h₂</em>
<em>0.343 mol of Na produce 0.343/2 = 0.1717 mol h₂</em>
<em>h2 = molecules * mw (molecular weight) =0.1717 * 2 =0.343 grams</em>
<em>Therefore the grams of hydrogen gas released is = 0.343 grams</em>
Answer:
A saturated solution can become supersaturated when it is cooled. The solubility of solid solutes in liquid solvents increases as the solvent is warmed up. For example, you can dissolve more sugar in warm water as opposed to cold water.