Question

2. Jacy bought a gold necklace weighing 21.3 grams from a flea market She filled a 10ml graduated cylinder with water to the 50 mL mark and dropped her necklace in. The level in the graduated cylinder rose to 7.4mL is her necklace real or fake? If not, identify the possible composition of her necklace
Gold: 19.3 g/cm^3
Copper 8.86 g/cm^3
Bronze: 9.87 g/cm^3​

Answer 1

Answer:

The necklace is fake.

The necklace is made up of copper.

Explanation:

The following data were obtained from the question:

Mass of the necklace = 21.3 g

Volume of water = 5 mL

Volume of water + Necklace = 7.4 mL

To identify the composition of the necklace, we shall determine the density of the necklace.

This can be obtained as follow:

We'll begin by calculating the volume of the necklace. This can be obtained as shown below:

Volume of water = 5 mL

Volume of water + Necklace = 7.4 mL

Volume of Necklace =.?

Volume of Necklace = (Volume of water + Necklace) – (Volume of water)

Volume of Necklace = 7.4 – 5

Volume of Necklace = 2.4 mL

NOTE:

1 mL = 1 cm³

Therefore,

Volume of Necklace = 2.4 mL = 2.4 cm³

Finally, we shall determine the density of the necklace as follow:

Mass of the Necklace = 21.3 g

Volume of Necklace = 2.4 cm³

Density of Necklace =?

Density = mass /volume

Density = 21.3 / 2.4

Density = 8.87 g/cm³

Therefore, the density of the necklace is 8.87 g/cm³.

From the question given above, we were told Jacy bought a gold necklace.

But comparing the density of necklace to the densities given above the necklace is obviously made of copper material.

Therefore, Jacy bought a fake gold necklace.