Half-life refers to the time taken for half of the atoms in a radioactive substance to decay. Therefore in 1 half-life the 80 mg of substance will reduce to 40 mg. In another half-life it will reduce from 40 mg to 20 mg, then in a third half-life from 20 mg to 10 mg. Therefore the half-life is equal to the total time taken to decay from 80 mg to 10 mg divided by 3:
t(1/2) = 36 hours / 3 = 12 hours.
Answer:
The answer is that ethane gas has a density of 1.34 g/L at STP
Explanation:
Ethane weighs 0.0013562 gram per cubic centimeter or 1.3562 kilogram per cubic meter, i.e. density of ethane is equal to 1.3562 kg/m³; at 0°C (32°F or 273.15K) at standard atmospheric pressure.
The pressure of the carbon dioxide will be 0.09079 atm.
<h3>What is partial pressure?</h3>
The pressure exerted by the individual gas is known as partial pressure.
The partial pressure is given as

In a mixture of carbon dioxide and oxygen, 40.0% of the gas pressure is exerted by oxygen.
If the total pressure is 115 mmHg.
The total pressure in atm will be
P = 115 mmHg
P = 0.15132 atm
We have

Then the pressure of the carbon dioxide will be 0.09079 atm.
More about the partial pressure link is given below.
brainly.com/question/13199169
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Do you know what is meant by needed? does it mean lone pairs?
Answer: None of the given options show polymer made up of H₂C=CH-CN (Acrylonitrile).
Explanation: Acrylonitrile (H₂C=CH-CN) which is a monomer on self linkage results in a large chain polymer called as
Polyacrylonitrile.
The structure of Polyacrylonitrile is as follow,
--(H₂C-CHCN-)n--Where n shows the number of Acrylonitrile units joined together in the formation of Polyacrylonitrile. This polymerization reaction can take place by different mechanisms including free radical mechanism, acid catalyzed addition or base catalyzed addition reaction.
The polymerization is shown below,