Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at
, 


Answer:
THE MOLARITY IS 2.22 MOL/DM3
Explanation:
The solution formed was as a result of dissolving 37.5 g of Na2S in 217 g of water
Relative molecular mass of Na2S = ( 23* 2 + 32) = 78 g/mol
Molarity in g/dm3 is the amount of the substance dissolved in 1000 g or 1 L of the solvent. So we have;
37.5 g of Na2S = 217 g of water
( 37.5 * 1000 / 217 ) g = 1000 g of water
So, 172.81 g/dm3 of the solution
So therefore, molarity in mol/dm3 = mol in g/dm3 / molar mass
Molarity = 172.81 g/dm3 / 78 g/mol
Molarity = 2.22 mol/dm3
The molarity of the solution is 2.22 mol/dm3
PH is defined as the negative log of Hydronium Ion concentration.
So, in order to find the pH of vinegar, we find the negative log of its hydronium ion concentration.
![pH=-log[ H_{3}O^{+}] \\ \\ pH=-log(1.6 * 10^{-3}) \\ \\ pH=2.8](https://tex.z-dn.net/?f=pH%3D-log%5B%20H_%7B3%7DO%5E%7B%2B%7D%5D%20%5C%5C%20%20%5C%5C%20%0ApH%3D-log%281.6%20%20%2A%2010%5E%7B-3%7D%29%20%20%5C%5C%20%20%5C%5C%20%0ApH%3D2.8)
So, the pH of given vinegar solution will be 2.8.
Therefore, the answer to this question is option B
Answer:

The prefix "Tetra" implies 4 Bromine atoms. The prefix "Deca" implies 10 fluorine atoms.
Option A
The price elasticity of demand measures buyers’ responsiveness to a change in the price of a good.
<u>Explanation:</u>
Price elasticity of demand holds the responsiveness of need subsequent a variation in a product's cost. In different terms, it’s a process to comprehend out the responsiveness of buyers to inconstancies in cost. Price elasticity estimates the responsiveness of the measure necessitated or outfitted of a good to a shift in its demand.
The price elasticity of demand is the rate fluctuation in the amount demanded of a good or assistance distributed by the percentage shift in the price. Considering the quantity demanded habitually declines with value, the price elasticity coefficient is essentially forever negative.