Density = mass/volume
so rearranged mass = volume x density
mass = 8.920 x 45 = 401.4g
rearrange (there are 1000grams in 1kg)
volume = mass/density
volume = 1000/8.920
volume = 112.1076233cm3
Bohrs model says that electrons move in fixed shells (which have fixed distances) around the nucleus of an atom.
Is the something missing from the question
B. Two significant figures
Your final answer can only have as many significant figures as the number that has the least amount of significant figures in it, which is (0.0065)
Answer:
163.2g
Explanation:
First let us generate a balanced equation for the reaction. This is shown below:
4Al + 3O2 —> 2Al2O3
From the question given, were were told that 3.2moles of aluminium was exposed to 2.7moles of oxygen. Judging by this, oxygen is excess.
From the equation,
4moles of Al produced 2moles of Al2O3.
Therefore, 3.2moles of Al will produce = (3.2x2)/4 = 1.6mol of Al2O3.
Now, let us covert 1.6mol of Al2O3 to obtain the theoretical yield. This is illustrated below:
Mole of Al2O3 = 1.6mole
Molar Mass of Al2O3 = (27x2) + (16x3) = 54 + 48 =102g/mol
Mass of Al2O3 =?
Number of mole = Mass /Molar Mass
Mass = number of mole x molar Mass
Mass of Al2O3 = 1.6 x 102 = 163.2g
Therefore the theoretical of Al2O3 is 163.2g
