A pure silver necklace melts into liquid at 1,763°F. A pure silver spoon melts at 1,763°F.
Is the melting point of a substance an example of an extensive or
intensive property? Explain how you know.

Intensive property

Explanation:

The melting point of a substance is the temperature at which a solid metal changes to liquid.

At this stage, the particles of the solid would have gained sufficient energy to break away from the well ordered lattice configuration and they begin to behave like liquids.

An intensive property of matter is a physical property of matte that does not change as the quantity of matter changes. Melting point is one of such property. In this problem, we know that the mass of a necklace is lesser compared to that of a pure sliver spoon. But the melting point remains the same. This is pure indication of intensive property.

An extensive property changes as the mass of the body changes.

A. 2.107x10^24

Explanation:

1 mole is defined as the particles containing in 12g of 12-C. That is 6.022x10²³ particles.

When you say 1 mole of atoms means 6.022x10²³ atoms, 1 mole of molecules means 6.022x10²³ molecules, etc.

Now, 3.5 moles of H₂O are:

3.5mol * (6.022x10²³ molecules / 1mol) = 2.107x10²⁴ molecules of H₂O.

Thus, right answer is:

A. 2.107x10^24