Question

b.4 calculate the number of moles of h₂ that are expected to form in each flask based on the number of moles of mg that will react and the equation for each reaction. (1 mole of h₂ is produced for every mole of mg reacted.)
a. the flask with 0.3 g mg 0.0123 mol
b. the flask with 0.6 g mg

c. the flask with 1.2 g mg

Explanation:

Step1: Calculate moles of Mg

The molar mass of Mg is \(M = 24.31\space g/mol\). The formula to calculate the number of moles \(n=\frac{m}{M}\), where \(m\) is the mass of the substance.
For part b: \(m = 0.6\space g\), \(n_{Mg}=\frac{0.6}{24.31}\space mol\approx0.0247\space mol\)
For part c: \(m = 1.2\space g\), \(n_{Mg}=\frac{1.2}{24.31}\space mol\approx0.0494\space mol\)

Step2: Determine moles of \(H_2\)

Since 1 mole of \(H_2\) is produced for every mole of Mg reacted (\(n_{H_2}=n_{Mg}\))
For part b: \(n_{H_2}\approx0.0247\space mol\)
For part c: \(n_{H_2}\approx0.0494\space mol\)

Answer:

b. \(0.0247\space mol\)
c. \(0.0494\space mol\)