<h3>
Answer:</h3>
250.756 moles He
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Explanation:</h3>
From the question we are given;
Volume, L = 685 L
Temperature, T = 621 K
Pressure, P = 189 × 10 kPa
We are required to calculate the number of moles of the gas,
Using the Ideal gas equation,
PV = nRT, where P is the pressure, V is the volume, T is the temperature, n is the number of moles, and R is the ideal gas constant.
We can replace the known variables and constant in the equation to get the unknown variable, n.
Using ideal gas constant as 8.3145 L.kPa/K/mol



n = 250.756 moles
The moles of helium contained in the sphere is 250.756 moles
Answer:
D- a weak base
Explanation:
The ph scale goes from 1-10 a solution over 7ph is classified as basic. A solution thats 8.4 is only 1.4 over 7pH, making it a weak basic solution. An example of a strong base would be a solution with a pH of 9.2 (for example).
Answer:
24.24 L
Explanation:
Boyle’s law, also called Mariotte’s law, a relation concerning the compression and expansion of a gas at constant temperature.
This empirical relation, formulated by the physicist Robert Boyle in 1662, states that the pressure (p) of a given quantity of gas varies inversely with its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant.
Real gases obey Boyle’s law at sufficiently low pressures, although the product pv generally decreases slightly at higher pressures, where the gas begins to depart from ideal behaviour.
As, PV = k
P₁ V₁ = P₂ V₂
Given P₁ = 101 KPa
V₁ = 6 L
P₂ = 25 kPa
So, V₂ = P₁ V₁ /P₂ = 101 *6/25 = 24.24 L
Energy is the correct answer. I hope I helped you
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