Note that the density of pure aluminum is 2.7 g/cm³ (from tables).
Given:
m = 39.0 g, the mass of the metal
V = 10.0 cm³, the density of the metal
By definition, the density of the metal is
density = mass/volume
= (39.0 g)/(10.0 cm³)
= 3.9 g/cm³
Answer:
The calculated density is not equal to 2.7 g/cm³, therefore the metal sphere is not made of pure aluminum.
Answer:
The limiting reactant is propene,
.
Explanation:

Moles of nitrogen propene = 2 mol
Moles of oxygen = 10 mol
According to reaction, 2 moles of propene reacts with 9 moles of oxygen gas, then 2 moles of propene will react with:

According to the question, we have 10 moles of oxygen gas, which is more than 9 moles of oxygen gas. This indicates that propene is present in a limiting amount hence, it is a limiting reactant.
The limiting reactant is propene, hence the correct answer is the
.
Answer:
When zinc is added to the solution of iron sulphate, the colour of iron sulphate solution changes. It is because zinc is more reactive than iron, it displaces iron from its solution of iron sulphate and a grey precipitate of iron and a colourless solution of zinc sulphate is formed.
Explanation:
Zn(s) + FeSO4(aq) -----> ZnSO4(aq) + Fe(ppt.)
They discovered that *elements* show increase in atomic numbers across the period.