Question

b.3 calculate the number of moles of magnesium that will react in each flask by comparing the number of moles of magnesium in the flask with the number of moles of magnesium that will react with the hcl. since 2 moles of hcl are required for each mole of magnesium, the number of moles of mg with will react with 0.05 moles of hcl is 0.05 moles hcl x (1 mole mg/2 moles hcl) = 0.025 moles mg. compare the moles of magnesium with the moles of magnesium that will react with hcl. the smaller value is the number of moles of magnesium that will react in that flask. circle the number of moles of magnesium that will react in each flask a. number of moles of mg in 0.3 grams flask a1. number of moles of mg which will react with 0.05 moles hcl b. number of moles of mg in 0.6 grams flask b1. number of moles of mg which will react with 0.05 moles hcl c. number of moles of mg in 1.2 grams flask c1. number of moles of mg which will react with 0.05 moles hcl

Explanation:

Step1: Calculate moles of Mg in each flask

Use the formula \(n=\frac{m}{M}\), where \(m\) is mass and \(M = 24.305\space g/mol\) (molar mass of Mg).

• For \(m = 0.3\space g\): \(n_{Mg}=\frac{0.3}{24.305}\approx0.0123\space mol\)
• For \(m = 0.6\space g\): \(n_{Mg}=\frac{0.6}{24.305}\approx0.0247\space mol\)
• For \(m = 1.2\space g\): \(n_{Mg}=\frac{1.2}{24.305}\approx0.0494\space mol\)

Step2: Determine moles of Mg reacting with HCl

Given \(n_{HCl}=0.05\space mol\), and from \(Mg + 2HCl=MgCl_{2}+H_{2}\), \(n_{Mg\space reacting\space with\space HCl}=\frac{0.05}{2}=0.025\space mol\)

Step3: Compare and circle the smaller value

• For \(a\): Compare \(0.0123\) and \(0.025\). Circle \(0.0123\)
• For \(b\): Compare \(0.0247\) and \(0.025\). Circle \(0.0247\)
• For \(c\): Compare \(0.0494\) and \(0.025\). Circle \(0.025\)

Answer:

• \(a\): \(0.0123\)
• \(b\): \(0.0247\)
• \(c\): \(0.025\)