Three solutions 39.0 ml of 0.2 m kno₃; 59.0 ml of 0.9 m ca(no₃)₂; and 63.0 ml of 0.345 m kcl were poured together to make one new solution. what is the concentration of cl⁻ after mixing? answer in units of mol/l.

[Cl⁻] = 0.135 M

Explanation:

The concentration of Cl⁻ is equal to the total moles of Cl⁻ divided by the total volume:

C = n/V

All of the moles of Cl⁻ come from dissociation of the KCl:

KCl ⇒ K⁺ + Cl⁻

We will calculate the moles of Cl⁻ based on the amount of KCl added by using the molar ratio of 1:1.

(0.345 mol/L)(63.0 mL) = (21.735 mmol KCl)(Cl⁻/KCl) = 21.735 mmol Cl⁻

Extra significant figure are kept to avoid round-off errors.

Now we can calculate the total volume, which is the sum of the volume of the three solutions added:

(39.0 mL) + (59.0 mL) + (63.0 mL) = 161.0 mL

Finally, we calculate the concentration of Cl⁻

[Cl⁻] = (21.735 mmol) / (161.0 mL) = 0.135 M

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

it's c. elements are placed in rows based on how may valencies electrons have.