The molecular equation :
MgI₂(aq) + Pb(NO₃)₂(aq) → Mg(NO₃)₂(aq) + PbI₂(s)
The net ionic equations
Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s)
<h3>Further explanation</h3>
Given
Word equation
Required
The molecular equations and the net ionic equations
Solution
The chemical equation can be expressed in terms of:
- word equation
- skeleton equation
- balanced equation
The equation of a chemical reaction can be expressed in the equation of the ions
When a spectator ions are removed, the ionic equation is called the net ionic equation
A molecular equation is a chemical equation that has been balanced and is written in molecular (not ionic) form
The molecular equation :
MgI₂(aq) + Pb(NO₃)₂(aq) → Mg(NO₃)₂(aq) + PbI₂(s)
the ionic equation :
Mg²⁺ +2I⁻ + Pb²⁺ + 2NO₃⁻ → Mg²⁺ + 2NO₃⁻ + PbI₂
the net ionic equations
Pb²⁺(aq) + 2I⁻(aq) → PbI₂(s)
Le Châtelier's principle tells us that chemical <span>c. equilibrium </span>will adjust in an attempt to remove a stressor.
Explanation:
It is known that in a simple cubic unit cell the atoms are only present at the corner of the unit cell. This means that there are in total 8 atoms present in a simple cubic unit cell.
Therefore, in one simple cubic unit cell sharing of one atom is only
.
Hence, the total number of atoms in a unit cell will be as follows.
= 1
Thus, we can conclude that there is 1 calcium atom present in each unit cell.
Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶


Density of iron bar

= 7870 kg/m³ (3 s.f.)
7.

Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³

Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume

(3 s.f.)