Answer:
Noble gases
Explanation:
The noble gases are non-metals that requires the highest amount of energy to remove an electron from their shells.
The reason for this difficult is that their electronic configuration confers a stable configuration them.
- The ionization energy is the energy required to remove the most loosely held electrons in an atom.
- Due to the special stability of noble gases, it is very difficult to remove electrons from an atom of noble gases.
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
Answer:
1.62 × 10²⁴ atoms are in 52.3 g of lithium hypochlorite.
Explanation:
To find the amount of atoms that are in 52.3 g of lithium hypochlorite, we must first find the amount of moles. We do this by dividing by the molar mass of lithium hypochlorite.
52.3 g ÷ 58.4 g/mol = 0.896 mol
Next we must find the amount of formula units, we do this be multiplying by Avagadro's number.
0.896 mol × 6.02 × 10²³ = 5.39 × 10²³ f.u.
Now to get the amount of atoms we can multiply the amount of formula units by the amout of atoms in one formula unit.
5.39 × 10²³ f.u. × 3 atom/f.u. = 1.62 × 10²⁴ atoms
1.62 × 10²⁴ atoms are in 52.3 g of lithium hypochlorite.
Answer:
It will reach to its maximum volume.
Explanation:
Using Ideal gas equation for same mole of gas as
:-
Given ,
V₁ = 65.0 mL
V₂ = ?
P₁ = 745 torr
The conversion of P(torr) to P(atm) is shown below:
So,
Pressure = 745 / 760 atm = 0.9803 atm
P₁ = 0.9803 atm
P₂ = 0.066 atm
T₁ = 25 ºC
T₂ = -5 ºC
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (25 + 273.15) K = 298.15 K
T₂ = (-5 + 273.15) K = 268.15 K
Using above equation as:
Solving for V₂ as:-
V₂ = 868 L
Given that:- V max = 835 L
<u>Thus, it will reach to its maximum volume.</u>
