Answer:
26.56g
Explanation:
The half life of an isotope decay is the time transcurred when the initial amount of the isotope decays to the half of its amount.
For the problem, when 1 half life transcur, the sample has a mass of:
425g / 2 = 212.5g
When 2 half lives transcur:
212.5g / 2 = 106.25g
3 half lives:
106.25/2 = 53.13g
And the amount that is found after 4 half lives is:
53.13/2 =
<h3>26.56g</h3>
The molarity of a Sodium carbonate solution : 0.373 M
<h3>Further explanation</h3>
Given
32.52 g Na₂CO₃
822 ml of solution = 0.822 L
Required
The molarity
Solution
Molarity shows the number of moles of solute in every 1 liter of solution.
mol of solute = mol of Na₂CO₃ :
= mass : MW Na₂CO₃
= 32.52 g : 106 g/mol
= 0.307
Molarity :
= n : V
= 0.307 mol : 0.822 L
= 0.373 M
Answer: The average rate of the reaction during this time interval is, 0.005 M/s
Explanation:
The given chemical reaction is:
The expression will be:
where,
= final concentration of 
= 0.025 M
= initial concentration of = 0.100 M
= final time = 15 minutes
= initial time = 0 minutes
Putting values in above equation, we get:
Hence, the average rate of the reaction during this time interval is, 0.005 M/s
Answer:
The boiling point of HF is <u><em>higher than</em></u> the boiling point of H2, and it is <u><em>higher than</em></u> the boiling point of F2.
Explanation:
In HF, inter- molecule forces will be present between the hydrogen and fluorine atoms. There will be hydrogen bonding present among the hydrogen and fluorine atoms. Hydrogen bonds are strong bonds and hence the boiling point for HF would be high as much energy will be required to break these bonds.
H2 and F2 will only have intra-molecular attractions and there will be no hydrogen bonds present in them. As a result, their boiling point will be lower.
Coal is not a mineral. It's not a mineral because minerals are inorganic. Coal is organic because it comes from decayed living matter.
