Amount of substance

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Question 43
Medium

When 380 mg of potassium is added to 480 cm3 of water at 22 ∘C22\text{ }^\circ\text{C}22 ∘C under a pressure of 98.0 kPa, a reaction occurs producing a gas.

a.

Write a balanced molecular equation for the reaction that occurs.

[1]
b.

Calculate the volume, in cm3\text{cm}^3cm3, of the gas formed. (The gas constant R=8.31 J K−1 mol−1R = 8.31\text{ J K}^{-1}\text{ mol}^{-1}R=8.31 J K−1 mol−1, relative atomic mass Ar(K)=39.1A_r(\text{K}) = 39.1Ar​(K)=39.1)

[3]
c.

Calculate the concentration, in mol dm−3\text{mol dm}^{-3}mol dm−3, of potassium ions in the resulting solution.

[2]

Amount of substance Questions

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