Answer:
94.4g/mol is molar mass of the unknown
Explanation:
Based on the freezing point depression equation:
ΔT = Kf*m*i
<em>Where ΔT is the depression in freezing point (1.87°C)</em>
<em>Kf is freezing point depression constant of water (1.86°Ckg/mol)</em>
<em>And i is Van't Hoff factor (1 for nonelectrolyte solutes)</em>
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Replacing:
1.87°C = 1.86°CKg/mol*m*i
1.005mol/kg solvent = m
Using the mass of the solvent we can find the oles of the nonelectrolyte:
1.005mol/kg solvent * 0.4764kg = 0.479moles
Molar mass is defined as the ratio between mass of a substance in grams and moles, that is:
45.2g / 0.479mol =
<h3>94.4g/mol is molar mass of the unknown</h3>
Answer: Volume of benzene is: 22.8 cm cubed
Answer:
Mass = 11 g
Explanation:
Given data:
Mass of Zn = 5 g
Mass of HCl = 50 g
Mass of hydrogen gas produced = 6 g
Mass of zinc chloride produced = ?
Solution:
Chemical equation:
Zn + 2HCl → ZnCl₂ + H₂
Number of moles of Zn:
Number of moles = mass / molar mass
Number of moles = 5 g / 65.38 g/mol
Number of moles = 0.08 mol
Number of moles of HCl :
Number of moles = mass / molar mass
Number of moles = 50 g / 36.5 g/mol
Number of moles = 1.4 mol
Now we will compare the moles of both reactant with zinc chloride.
Zn : ZnCl₂
1 : 1
0.08 : 0.08
HCl : ZnCl₂
2 : 1
1.4 : 1/2×1.4 =0.7 mol
The number of moles of zinc chloride produced by Zn are less so it will limiting reactant.
Mass of zinc chloride:
Mass = number of moles × molar mass
Mass = 0.08 mol × 136.3 g/mol
Mass = 11 g
The forces between particles are called intermolecular forces. A strong intermolecular force means that the particles are tightly paced and is associated with the solid phase. Moderate intermolecular force is associated with the liquid state and little to no intermolecular force is associated with the gaseous state. Temperature has a direct effect on the state of matter in which the substance exists has. Generally speaking, a rise in tempreature changes a substance from the solid to liquid phase and from liquid to gaseus phase. The reverse is true, if the temperature lowers then the substance will go from gas to liquid and liquid to solid. It is important to not that temperature affects intermolecular forces. As the temperature increases then the individual particles become excited and gain enough energy to over the intermolecular forces and so the particles seperate from each other.
This is an exercise in the general or combined gas law.
To start solving this exercise, we obtain the following data:
<h3>
Data:</h3>
- T₁ = 22.5 °C + 273 = 295.5 K
- P₁ = 1.95 atm
- V₁ = ¿?
- P₂ = 3.69 atm
- T₂ = 11.9 °C + 273 = 284.9 k
- V₂= 56.4 ml
We use the following formula:
P₁V₁T₂ = P₂V₂T₁ ⇒ General formula
Where
- P₁ = Initial pressure
- V₁ = Initial volume
- T₂ = Initial temperature
- P₂ = Final pressure
- V₂ = final volume
- T₁ = Initial temperature
We clear the formula for the initial volume:
We substitute our data into the formula to solve:
The helium-filled balloon has a volume of <u>110.697 ml.</u>
