1/8=(1/2)^3 and the half life of radon is 3.8days
Half life is the time it takes for half of any amount of a radioactive substance to decay into something else.
Therefore for a sample of radon to decay to 1/8 of its original amount, it would take 3 x 3.8days=11.4 days
Answer:
pH value of a solution depends on the concentration of hydrogen ions
(pH = -log[H+(aq)].
Hydrochloric acid is a strong acid, while ethanoic acid is a weak acid. Strong acids ionize completely in water (to give ions which includes H+(aq)), while weak acids only ionize partially in water.
Therefore, even if both hydrochloric acid and ethanoic acid are monobasic acids (each molecule can ionize completely to give 1 hydrogen ion), since hydrochloric acid ionizes completely in water and ethanoic acid does not ionize completely, the concentration of hydrogen ions in hydrochloric acid is higher than that of ethanoic acid, leading to a lower pH value for hydrochloric acid, while higher for ethanoic acid.
Answer:
The correct answer is 146 g/mol
Explanation:
<em>Freezing point depression</em> is a colligative property related to the number of particles of solute dissolved in a solvent. It is given by:
ΔTf = Kf x m
Where ΔTf is the freezing point depression (in ºC), Kf is a constant for the solvent and m is the molality of solution. From the problem, we know the following data:
ΔTf = 1.02ºC
Kf = 5.12ºC/m
From this, we can calculate the molality:
m = ΔTf/Kf = 1.02ºC/(5.12ºC/m)= 0.199 m
The molality of a solution is defined as the moles of solute per kg of solvent. Thus, we can multiply the molality by the mass of solvent in kg (250 g= 0.25 kg) to obtain the moles of solute:
0.199 mol/kg benzene x 0.25 kg = 0.0498 moles solute
There are 0.0498 moles of solute dissolved in the solution. To calculate the molar mass of the solute, we divide the mass (7.27 g) into the moles:
molar mass = mass/mol = 7.27 g/(0.0498 mol) = 145.9 g/mol ≅ 146 g/mol
<em>Therefore, the molar mass of the compound is 146 g/mol </em>
Answer:
It means the chemical entity is a radical
Explanation:
When we talk of unsaturation, we are referring to the number of pi-bonds in a chemical entity. The alkane, alkene and alkyne organic family are used to as common examples to explain the term unsaturation.
While alkynes have 3 bonds, it must be understood that they have 2 pi bonds only and as such their degree of saturation is two.
In the case of an alkene, there is only one single pi bond and as such the degree of unsaturation is 1.
Now in this case, we have a fractional 0.5 degree of unsaturation alongside the 3 to make a total of 3.5. So what’s the issue here?
The fractional part shows that the chemical entity we are dealing with here is a radical. While the integer 3 shows that there are 3 pi-bonds, the half pi bond remaining tells us that there is a missing electron on one of the atoms involved in the chemical bonding and as such, the 1/2 extra degree of unsaturation tends to tell us this.
Kindly recall that a radical is a chemical entity within which we have at the least an unpaired electron.
Answer:
All elements in the same A group will have the same number of
valence electrons.
Explanation:
Group A has 1 valence electrons.
