Pyrite because it doesn’t sink it floats
Answer:
The concentration of the most dilute solution is 0.016M.
Explanation:
First, a solution is prepared and then it undergoes two subsequent dilutions. Let us calculate initial concentration:
![[Na_{2}SO_{4}]=\frac{moles(Na_{2}SO_{4})}{liters(solution)} =\frac{mass((Na_{2}SO_{4}))}{molarmass(moles(Na_{2}SO_{4}) \times 0.100L)} =\frac{2.5316g}{142g/mol\times 0.100L } =0.178M](https://tex.z-dn.net/?f=%5BNa_%7B2%7DSO_%7B4%7D%5D%3D%5Cfrac%7Bmoles%28Na_%7B2%7DSO_%7B4%7D%29%7D%7Bliters%28solution%29%7D%20%3D%5Cfrac%7Bmass%28%28Na_%7B2%7DSO_%7B4%7D%29%29%7D%7Bmolarmass%28moles%28Na_%7B2%7DSO_%7B4%7D%29%20%5Ctimes%200.100L%29%7D%20%3D%5Cfrac%7B2.5316g%7D%7B142g%2Fmol%5Ctimes%200.100L%20%7D%20%3D0.178M)
<u>First dilution</u>
We can use the dilution rule:
C₁ x V₁ = C₂ x V₂
where
Ci are the concentrations
Vi are the volumes
1 and 2 refer to initial and final state, respectively.
In the first dilution,
C₁ = 0.178 M
V₁ = 15 mL
C₂ = unknown
V₂ = 50 mL
Then,

<u>Second dilution</u>
C₁ = 0.053 M
V₁ = 15 mL
C₂ = unknown
V₂ = 50 mL
Then,

Answer:
Option (d) chlorine has a greater ionization energy than sodium
Explanation:
Ionization energy is the energy required to remove an electron from a gaseous atom or ion. Sodium has just 1 electron in it's outmost shell and chlorine has 7.
Sodium needs 7 electrons to complete it's octet configuration and chlorine needs just 1.
Sodium can not attract 7 electrons to complete it's octet configuration instead it will easily lose the 1 electron in it's outmost shell to form cation. On the other hand, it will be difficult for chlorine to lose any of it's outmost electrons. This makes chlorine to have higher ionization energy than sodium.
Here is the correct question
You mix 125 mL of 0.170 M CsOH with 50.0 mL of 0.425 M HF in a coffee-cup calorimeter, and the temperature of both solutions rises from 20.20 °C before mixing to 22.17 °C after the reaction. What is the enthalpy of reaction per mole of ? Assume the densities of the solutions are all 1.00 g/mL, and the specific heat capacities of the solutions are 4.2 J/g · K. Enthalpy of reaction = kJ/mol
Answer:
75.059 kJ/mol
Explanation:
The formula for calculating density is:

Making mass the subject of the formula; we have :
mass = density × volume
which can be rewritten as:
mass of the solution = density × volume of the solution
= 1.00 g/mL × (125+ 50 ) mL
= 175 g
Specific heat capacity = 4.2 J/g.K
∴ the energy absorbed is = mcΔT
= 175 × 4.2 × (22.17 - 20.00) ° C
= 1594.95 J
= 1.595 J
number of moles of CsOH = 
= 0.2125 mole
Therefore; the enthalpy of the reaction = 
= 
= 75.059 kJ/mol