In a reaction Mg(s) + 2HCl(aq) →H2(g) + MgCl2(aq), 6.00 g of Mg was present at 0.00 min. After 3.00 min, 4.50 g of Mg remained. Express the average rate as mol of Mg consumed per minute.
g Mg changed = 6.00 - 4.50 = 1.50
mols Mg = grams/atomic mass = ?
Then rate = delta mols/delta time.
To calculate the average rate of a reaction, we need to determine the change in the amount of reactant over a specific time period. In this case, we are given the initial amount of Mg and the amount remaining after a certain time. We can use this information to find the average rate in mol of Mg consumed per minute.
First, we need to convert the masses of Mg given into moles. The molar mass of Mg is 24.31 g/mol. Therefore, the initial amount of Mg can be calculated as follows:
Initial amount of Mg = (mass of Mg / molar mass of Mg)
= (6.00 g / 24.31 g/mol)
= 0.247 mol
Similarly, we need to determine the amount of Mg remaining after 3.00 minutes. We can calculate it using the given mass and the molar mass of Mg:
Amount of Mg remaining = (mass of Mg remaining / molar mass of Mg)
= (4.50 g / 24.31 g/mol)
= 0.185 mol
Next, we calculate the change in the amount of Mg:
Change in amount of Mg = (initial amount of Mg - amount of Mg remaining)
= (0.247 mol - 0.185 mol)
= 0.062 mol
Now, we can calculate the average rate of the reaction as the change in amount of Mg per time period:
Average rate = (Change in amount of Mg / Time period)
= (0.062 mol / 3.00 min)
= 0.021 mol/min
Therefore, the average rate of the reaction is 0.021 mol of Mg consumed per minute.