The height of the described cylinder is 0.85 cm
Mass= 98g
Density= 8.9g/cm^3
Density= (mass/volume)
Substitute the values
8.94= 98/ volume
Volume=
Volume= 10.97
Volume of a cylinder can be found with (V = π r 2 h.)
h= height of cylinder ?
radius= 2cm
Substitute the values
10.97= π × × h
h= 10.97/12.57
h= 0.85 cm
Therefore, height of the described cylinder is 0.85 cm
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The answer is 9.99 μL
9.99 μL of HCL is to be added to the unbuffered solution to change the pH from 10.00 to 3.8
pH is the measure of acidity or basicity of the given solution due to presence of hydrogen and hydronium ions. As the solution is indicated as unbuffered the HCL added dissociates completely and increases the molarity of hydronium ions.
To calculate molarity of hydronium ions in the initial condition, pH=10.00
Initial hydronium ions= 10⁻¹⁰=1.0✕10--10 M
Final hydronium ions=10⁻3.8= 1.5✕10-4 M
Molarity is defined by the formula number moles divided by the volume of the solution, to find the number of moles of hydronium ions that multiply volume and molarity.
Initial moles of hydronium ions= 0.4✕1.0✕10--10 =4✕10--12 moles
Final moles of hydronium ions= 0.4✕1.5✕10-4 =6 x 10-5 moles
Change in hydronium ions=(6 x 10-5)-(4✕10--12 )= 5.99x10-5 moles
Volume of HCL required=5.99x10-5 ✕(1/6)= 9.99 μL
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Answer: the correct answer is D) None of the individual insects should have possessed genomes that made them resistant to DDT.
Explanation: the problem is that DDT has become ineffective because insects have become more resistant to DDT.
We can use the ideal gas law equation to find the volume occupied by the gas
PV = nRT
where
P - pressure - 1.33 atm x 101 325 Pa/atm = 134 762 Pa
V - volume
n - number of moles - 18.0 g / 4 g/mol = 4.5 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in Kelvin - 29 °C + 273 = 302 K
substituting these values in the equation
134 762 Pa x V = 4.5 mol x 8.314 Jmol⁻¹K⁻¹ x 302 K
V = 83.8 L
volume occupied by He is 83.8 L