Answer :
The concentration of 
before any titrant added to our starting material is 0.200 M.
The pH based on this ion concentration is 0.698
Explanation :
First we have to calculate the concentration of before any titrant is added to our starting material.
As we are given:
Concentration of HBr = 0.200 M
As we know that the HBr is a strong acid that dissociates complete to give hydrogen ion and bromide ion 
.
As, 1 M of HBr dissociates to give 1 M of
So, 0.200 M of HBr dissociates to give 0.200 M of
Thus, the concentration of before any titrant added to our starting material is 0.200 M.
Now we have to calculate the pH based on this ion concentration.
pH : It is defined as the negative logarithm of hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
Thus, the pH based on this ion concentration is 0.698
Answer:
2. 181.25 K.
3. 0.04 atm.
Explanation:
2. Determination of the temperature.
Number of mole (n) = 2.1 moles
Pressure (P) = 1.25 atm
Volume (V) = 25 L
Gas constant (R) = 0.0821 atm.L/Kmol
Temperature (T) =?
The temperature can be obtained by using the ideal gas equation as illustrated below:
PV = nRT
1.25 × 25 = 2.1 × 0.0821 × T
31.25 = 0.17241 × T
Divide both side by 0.17241
T = 31.25 / 0.17241
T = 181.25 K
Thus, the temperature is 181.25 K.
3. Determination of the pressure.
Number of mole (n) = 10 moles
Volume (V) = 5000 L
Temperature (T) = –10 °C = –10 °C + 273 = 263 K
Gas constant (R) = 0.0821 atm.L/Kmol
Pressure (P) =?
The pressure can be obtained by using the ideal gas equation as illustrated below:
PV = nRT
P × 5000 = 10 × 0.0821 × 263
P × 5000 = 215.923
Divide both side by 5000
P = 215.923 / 5000
P = 0.04 atm
Thus, the pressure is 0.04 atm
2KClO₃ → 2KCl + 3O₂
mole ratio of KClO₃ to O₂ is 2 : 3
∴ if moles of O₂ = 5 mol
then moles of KClO₃ =
= 3.33 mol
Mass of KClO₃ needed = mol of KClO₃ × molar mass of KClO₃
= 3.33 mol × ((39 × 1) + (35.5 × 1) + (16 × 3) g/mol
= 407.93 g
<span>0.6 = mass/1.2 </span>
<span>mass = 0.6 x 1.2 </span>
<span>= 0.72 g </span>
