Question

A 75 gram solid cube of mercury (II) oxide has a density of 2.4 x 103 kg/m3 .

What is the length of one side of the cube in cm?

The mercury (II) oxide completely dissociates and forms liquid mercury and oxygen gas. Write a balanced chemical equation and indicate if this process is a chemical or physical change?

The oxygen gas escapes and now you are left with liquid grey substance. Is this grey substance a compound, element, homogeneous mixture or heterogeneous mixture?

Answer 1

0.031 m

HgO(s) ⇒ Hg(l) + 1/2 O₂(g)

Chemical change

Element

Step-by-step explanation:

A 75 gram solid cube of mercury (II) oxide has a density of 2.4 × 10³ kg/m³. What is the length of one side of the cube in cm?

Step 1: Convert the mass to kilograms

We will use the relationship 1 kg = 1,000 g.

`75g * (1kg)/(1,000g) = 0.075kg`

Step 2: Calculate the volume (V) of the cube

`0.075kg * (1m^(3) )/(2.4 * 10^(3) kg) = 3.1 * 10^(-5) m^(3)`

Step 3: Calculate the length (l) of one side of the cube

We will use the following expression.

`V = l^(3) \\l = \sqrt[3]{V} = \sqrt[3]{3.1 * 10^(-5) m^(3) }=0.031m`

The mercury (II) oxide completely dissociates and forms liquid mercury and oxygen gas. Write a balanced chemical equation and indicate if this process is a chemical or physical change?

The balanced chemical equation is:

HgO(s) ⇒ Hg(l) + 1/2 O₂(g)

This is a chemical change because new substances are formed.

The oxygen gas escapes and now you are left with liquid grey substance. Is this grey substance a compound, element, homogeneous mixture or heterogeneous mixture?

The liquid gray substance is Hg(l), which is an element because it is formed by just one kind of atoms.