Answer:
259.497 mg, 58.84%
Explanation:
BaSO₄ → Ba²⁺ + SO₄²⁻
to calculate the mole of BaSO₄
mole BaSO₄ = mass given / molar mass = 403 mg / 233.38 g/mol = 1.7268 mol
comparing the mole ratio
1.7268 mol of BaSO₄ yields 1.7268 mol of Ba²⁺
403 mg BaSO₄ yields ( 1.7268 × 137.327 ) where 137.327 is the molar mass of Barium mol of Ba²⁺
441 mg BaSO₄ will yield ( 1.7268 × 137.327 × 441 mg ) / 403 mg = 259 .497 mg
mas percentage of the Barium compound = 259 .497 mg / 441 mg × 100 = 58.84%
Answer:
8.33 hours
Explanation:
In order to solve this problem, we must apply Graham's law of diffusion in gases. Graham's law states that the rate of diffusion of a gas is inversely proportional to the square root of its vapour density. For two gases we can write;
R1/R2=√d2/d1
Where;
R1= rate of diffusion of hydrogen
R2= rate diffusion of unknown gas
d1= vapour density of hydrogen
d2= vapour density of the unknown gas
Volume of hydrogen gas = 360cm^3
Time taken for hydrogen gas to diffuse= 1 hour =3600 secs
R1 = 360 cm^3/3600 secs = 0.1 cm^3 s-1
Vapour density of unknown gas = 25
Vapour density of hydrogen = 1
Substituting values,
0.1/R2 = √25/1
0.1/R2 = 5/1
5R2 = 0.1 × 1
R2 = 0.1/5
R2= 0.02 cm^3s-1
Volume of unknown gas = 600cm^3
Time taken for unknown gas to diffuse= volume of unknown gas/ rate of diffusion of unknown gas
Time taken for unknown gas to diffuse= 600/0.02
Time= 30,000 seconds or 8.33 hours
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 deltaHrxn = -243 kJ/mol the deltaHrxn of CH4(methane) = -802 kJ/mol
The fuel that yields more energy per mole is METHANE. The negative sign merely signifies the release of energy. Thus, 802 kJ/mol is greater than 243 kJ/mol.
The fuel that yields more energy per gram is HYDROGEN. Here is the computation:
deltaHrxn = (-243 kJ/mol)(1 mol/2.016 g H2) <span>= -120.535714286 kJ/g or -121 kJ/g
</span>deltaHrxn of CH4(methane) = (-802 kJ/mol)(1 mol/16.04 g)
<span>= -50 kJ/g
</span>
As discussed the negative sign serves as the symbol of released energy. Thus, 121 is greater than 50.
