Answer:
May be the instrument is incorrect or may be error in it.
Explanation:
The copper have not been detected by this test because the test may be not for the detection of copper, may be it is used for identification of another minerals. If there is copper in the lake sample but can't be detected in the test so it means that the instrument which is used for detection is not the right one or having error in that instrument. Every mineral has a specific type of instrument that detect its presence, if we use incorrect instrument for the mineral then we can't detect the presence of that specific mineral.
C I think is the right answer
<u>Answer:</u> The number of
ions dissociated are
<u>Explanation:</u>
We are given:
pH = 2.07
Calculating the value of pOH by using equation, we get:

To calculate hydroxide ion concentration, we use the equation to calculate pOH of the solution, which is:
![pOH=-\log[OH^-]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%5BOH%5E-%5D)
We are given:
pOH = 11.93
Putting values in above equation, we get:
![11.93=-\log[OH^-]](https://tex.z-dn.net/?f=11.93%3D-%5Clog%5BOH%5E-%5D)
![[OH^-]=10^{-11.93}=1.17\times 10^{-12}M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D10%5E%7B-11.93%7D%3D1.17%5Ctimes%2010%5E%7B-12%7DM)
To calculate the number of moles for given molarity, we use the equation:

Molarity of solution = 
Volume of solution = 1243 mL = 1.243 L (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:

According to mole concept:
1 mole of a compound contains
number of particles
So,
number of
will contain =
number of ions
Hence, the number of
ions dissociated are
Answer:
Mass = 5.56 g
Explanation:
Given data:
Mass of Cl₂ = 4.45 g
Mass of NaCl produced = ?
Solution:
Chemical equation:
2Cl₂ + 4NaOH → 3NaCl + NaClO₂ + 2H₂O
Number of moles of Cl₂:
Number of moles = mass/molar mass
Number of moles = 4.45 g/ 71 g/mol
Number of moles = 0.063 mol
Now we will compare the moles of Cl₂ with NaCl.
Cl₂ : NaCl
2 : 3
0.063 : 3/2×0.063 =0.095 mol
Mass of NaCl:
Mass = number of moles × molar mass
Mass = 0.095 mol × 58.5 g/mol
Mass = 5.56 g