Answer:
See explanation
Explanation:
Dilution law= C1V1=C2V2.
Where C is the concentration in mol per dm cube and V= volume in dm cube.
From the questions the parameters given are; V= 42.5ZmL, concentration or molarity of HCl= 0.193M and the molarity of KOH = 0.125M.
(a). At 0mL where the base KOH has not been added yet.
Moles of HCl = molarity × volume.
Moles of HCl = 0.193 × 42.5/1000
Moles of HCl= 0.00820205
pH=- log 0.0082025
pH= 2.086
Approximately, pH=2.1.
(b). At 3mL of 0.125M KOH
3/1000 × 0.125 mol/L
= 0.003L× 0.125 M
= 0.000375 moles KOH
Determining the number of moles of HCl, we have;
42.5/1000 × 0.193 mol/L
= 0.0082025
Final volume= 3mL+42.5mL= 45.5 ml
Final[HCl] = 0.0082025 - 0.000375 = 0.0078275.
Therefore, 0.0078275/ 0.0455
= 0.1720
pH= -log 0.1720
pH= 0.76.
(c). 5mL of 0.125M KOH
5/1000 × 0.125
= 0.005×0.125
= 0.000625 mol KOH
42.5/1000 × 0.193 mol/L
= 0.0082025 mol
Final volume= 5mL + 42.5= 47.5 mL.
0.0082025-0.000625= 0.0076
Final [HCl] = 0.0076/0.0475
= 0.16
pH= -log 0.16
pH= 0.79.
Answer:
2.8 m
Explanation:
Step 1: Given data
- Moles of potassium bromide (solute): 0.210 mol
- Mass of water (solvent): 0.075 kg
Step 2: Calculate the molality of the solution
Molality is a unit used to express the concentration of a solution. It is equal to the moles of solute divided by the kilograms of solvent.
m = moles of solute / kilograms of solvent
m = 0.210 mol / 0.075 kg
m = 2.8 mol/kg = 2.8 m
<span>First, you should know that the four properties given are used in the identification of minerals. Hardness is the level of difficulty with which the smooth surface of a mineral sample may be scratched. Cleavage is how the crystal splits along a plane. Color is the result of the reflection of the light by the atoms and Streak is the color displayed by the mineral when it is crushed to a fine powder, while impurity contents affect the color, they do not affect the streak. So, streak is a better technique to identify minerals than colors. And the other two, hardness and cleavage are well known as being very useful. So, the least useful is color. Answer: option D.) color.</span>
Answer:
Explanation:
You need the conversion factor to convert the value of 12.33 kPa to milimiters of mercury, mmHg.
The converstion factors are looked at tables, which today you can find in internet.
Since the conversions between kPa and atm and between atm and mmHg are more widely known, I will show the conversion using those relations:
⇒ 101.325 kPa = 760 mmHg
Then, dividing both sides by 101.325 kPa you get the conversion factor:
- 1 = 760 mmHg / 101.325 kPa
Now, multiply 12.33 kPa by that conversion factor:
- 12.33 kPa × 760 mmHg / 101.325 kPa = 92.48 mmHg ← answer
Answer:
Molar mass of P₂O₅ = 141.948 g/mol which is approximately 142 g/mol.
Explanation:
Molar mass of AlCl₃
Molar mass = 26.982 + 35.5 × 3 = 133.32 g/mol
Molar mass of BaCl₂
Molar mass = 137.33 + 35.5 × 2 = 208.33 g/mol
Molar mass of MgCl₂
Molar mass = 24.305 + 35.5×2 = 95.305 g/mol
Molar mass of P₂O₅
Molar mass = 30.974×2 + 16× 5 = 141.948 g/mol