Answer: Therefore, the molar mass of the unknown substance is 68.4 g/mol.
Explanation: We can use the freezing point depression equation to solve for the molar mass of the unknown substance:
ΔT = Kf × m
where ΔT is the change in freezing point, Kf is the freezing point depression constant of the solvent (naphthalene), and m is the molality of the solution.
First, we need to calculate the molality of the solution:
molality = moles of solute / mass of solvent (in kg)
We don't know the number of moles of the unknown substance, but we can assume that the naphthalene does not contribute significantly to the total mass of the solution (since its mass is much smaller than the mass of the unknown substance). Therefore, we can use the entire mass of the solution (1000g + 12.3g = 1012.3g) as the mass of solvent.
mass of solute = 1000g
mass of solvent = 12.3g
mass of solution = 1012.3g
molality = (1000g / molar mass) / (12.3g / 1000g) = 81.3 / molar mass
Next, we need to calculate the change in freezing point:
ΔT = 1.2∘C
Finally, we can use the freezing point depression constant of naphthalene to solve for the molar mass of the unknown substance:
Kf for naphthalene = 6.8∘C/m
ΔT = Kf × m
1.2 = 6.8 × (81.3 / molar mass)
molar mass = 68.4 g/mol
Therefore, the molar mass of the unknown substance is 68.4 g/mol.
(2) Pb(CrO4)2 (4) Pb2(CrO4)3
Lead chromate and lead sulfate are found in the crystal Pb(Cr, S)O₄, which is a changeable solid mixed phase. This material is the end product of a co-precipitation reaction between lead and chrome salts (see the chapter on production and usage for further information). The correct option is 1.
Water does not dissolve lead chromate, which is produced by the double decomposition process. It is also used as a pigment and is referred to as chrome yellow. In a media that has been buffered with a solution of acetic acid and lead acetate, the lead precipitates as chrome.
There may be significant amounts of water-soluble lead compounds in lead chromate pigments. The formula that represents Lead (II) Chromate is PbCrO₄.
Thus the correct option is 1.
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Answer: 656 mmHg
Explanation:
Manometers are used to measure the pressure in a container by comparing it to normal atmospheric pressure.
First convert the atmospheric pressure to mmHg
1 torr = 1 mmHg
Therefore, the atmospheric pressure = 742 mmHg
Since the arm connected is higher than the level of the Mercury open to the atmosphere, then the gas pressure is lower than the atmospheric pressure.
Hence,
Pgas = Patm - change in height
Pgas = 742 mmHg - 8.6 cmHg
Balance the unit: 10 mm = 1 cm
Then,
Pgas = 742 mmHg - 86 mmHg
Pgas = 656 mmHg
The gas pressure in the container is 656 mmHg.
pOH scale is used to determine the basicity of a solution
pH scale is used to determine the acidity of a solution
pH and pOH are related in the following formula
pH + pOH = 14
once pOH is known we can calculate pH
pOH = 8.7
pH = 14 - 8.7
pH = 5.3
pH of the solution is 5.3
when pH is less than 7 the solution is said to be acidic
when pH is equal to 7 then solution is neutral
when pH is more than 7 then solution is basic
the pH of the solution here is 5.3 which is less than 7, therefore solution is acidic
acidic solution with pH of 5.3
a. Cl, Br, Ga
Answer:
Br,Ga,Cl?
Explanation: