Answer:
Benzene: 37.5 Torr
Methylbenzene: 12.5 Torr
Explanation:
By Raoult's Law, each substance in a gas mixture contributes to the total pressure of the mixture proportionally to their respective mole fraction. So,
Ppartial = x*P°
Where x is the mole fraction (0.5 for each one because it's equimolar), and P° is the vapor pressure.
Benzene: Ppartial = 0.5 * 75 = 37.5 Torr
Methylbenzene: Ppartial = 0.5 * 25 = 12.5 Torr
<h3>Answer:</h3>
Curium-247 <em>i.e.</em> ²⁴⁷₉₆Cm
<h3>Explanation:</h3>
Alpha decay is given by following general equation,
ᵃₓA → ⁴₂He + ᵃ⁻⁴ₓ₋₂B
Where;
A = Parent Isotope
B = Daughter Isotope
ᵃ = Mass Number
ₓ = Atomic Number
Californium-251 is the parent isotope in our case and it has 98 protons (atomic number) and is given as,
²⁵¹₉₈Cf
The alpha decay reaction of Californium-251 will be as,
²⁵¹₉₈Cf → ⁴₂He + ²⁴⁷₉₆B
The symbol for B with atomic number 96 was found to be the atom of Curium (Cm) by inspecting periodic table. Hence, the final equation is as follow,
²⁵¹₉₈Cf → ⁴₂He + ²⁴⁷₉₆Cm
-they are inside the nucleus of an atom
- they have a relative charge of +1
- they have a relative mass of 1
Answer:
Example
0.5 mol of sodium hydroxide is dissolved in 2 dm3 of water. Calculate the concentration of the sodium hydroxide solution formed.
Concentration =
Concentration = 0.25 mol/dm3
Volume units
Volumes used in concentration calculations must be in dm3, not in cm3. It is useful to know that 1 dm3 = 1000 cm3. This means:
divide by 1000 to convert from cm3 to dm3
multiply by 1000 to convert from dm3 to cm3
For example, 250 cm3 is 0.25 dm3 (250 ÷ 1000). It is often easiest to convert from cm3 to dm3 before continuing with a concentration calculation.
Question
100 cm3 of dilute hydrochloric acid contains 0.02 mol of dissolved hydrogen chloride. Calculate the concentration of the acid in mol/dm3.
Reveal answer
Converting between units
The relative formula mass of the solute is used to convert between mol/dm3 and g/dm3:
to convert from mol/dm3 to g/dm3, multiply by the relative formula mass
to convert from g/dm3 to mol/dm3, divide by the relative formula mass
Remember: the molar mass is the Ar or Mr in grams per mol.
Example
Calculate the concentration of 0.1 mol/dm3 sodium hydroxide solution in g/dm3. (Mr of NaOH = 40)
Concentration = 0.1 × 40
= 4 g/dm3
