In this question, you are given the density (2.7g/ml) and the volume of the aluminum. You are asked how much the volume is. To answer this question, you need to convert the volume into mass. Since the unit used is already same, you don't need to convert it into another unit. The calculation would be:
mass= volume / density
mass= 405ml / (2.70 g/ml)
mass= 150grams
Answer:

Explanation:
Hello,
In this case, it is convenient to compute the car's mileage in km/L as follows:

In such a way, since the distance is measured to be 250 km, the volume requirement is:

Regards.
The answer is: 27 grams of aluminium.
Balanced chemical reaction: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂.
n(H₂) = 1.5 mol; amount of hydrogen.
Form chemical reaction: n(Al) : n(H₂) = 2 : 3.
n(Al) = 2 · 1.5 mol ÷ 3.
n(Al) = 1.0 mol; amount of aluminium.
m(Al) = n(Al) · M(Al).
m(Al) = 1 mol · 27 g/mol.
m(Al) = 27 g; mass of aluminium.
True.
A mixture is composed of two or more pure substance that are physically combined but are not combined chemically and thus no electrons (of their atoms) are involved.
The primary properties of a mixture include:
1. The components of a mixture are easily separated
2. The components each keep their original properties.
3. The proportion of the components may vary.
There are two main categories of mixtures:
1. Heterogeneous mixtures - substances are not evenly distributed e.g. oil and water mixture
2. Homogeneous mixtures - substances are evenly distributed throughout the mixture e.g. salt water, air.