A homogenous mixture of metals is called an alloy. An alloy is found to be 30% by volume gold with the rest being aluminum. Aluminum has a density of 2.70 g/cm³. Gold has a density of 13.1 g/cm³. If a piece of alloy contains 3.70 lbs. of gold, how many kg of aluminum does it contain?

70 percent aluminum.

convert lbs gold to grams.

massalloy=massgold/.30

massaluminum=.7 * massalloy

To solve this problem, we can use the information given to find the volume of gold and then calculate the volume of aluminum. Once we have the volume of aluminum, we can convert it to mass using its density.

First, let's find the volume of gold in the alloy. We are told that the alloy is 30% gold by volume, so the remaining 70% must be aluminum.

Since the gold constitutes 30% of the total volume, the volume percentage of aluminum is 100% - 30% = 70%.

Next, let's find the volume of gold. Let's assume the volume of the alloy to be 1 cm³ for simplicity.

Volume of gold = 30% of 1 cm³ = 0.30 cm³

Now, let's find the volume of aluminum.

Volume of aluminum = 70% of 1 cm³ = 0.70 cm³

Next, let's convert the volume of aluminum to mass using its density.

Density of aluminum = 2.70 g/cm³

Mass of aluminum = Volume of aluminum * Density of aluminum
= 0.70 cm³ * 2.70 g/cm³

To convert this mass from grams to kilograms, we divide by 1000:

Mass of aluminum = (0.70 cm³ * 2.70 g/cm³) / 1000
= 1.89 g / 1000
= 0.00189 kg

Therefore, the alloy contains 0.00189 kg of aluminum.