The balanced equation :
<em>2Al₂O₃⇒ 4Al+3O₂</em>
<h3>Further explanation</h3>
Given
Reaction
Al₂O₃⇒ Al+O₂
Required
Balanced equation
Solution
A chemical reaction is said to be balanced if the number of elements involved in the reaction is the same (either the reactants or the products)
The reaction above is said to be unbalanced because the number of elements Al and O in the reactants and products is not the same.
The balancing step
1. Give a coefficient
Al₂O₃⇒ aAl+bO₂
2. Make an equation
Al, left = 2, right = a⇒a=2
O, left = 3, right = 2b⇒2b=3⇒b=3/2
The equation becomes :
Al₂O₃⇒ 2Al+3/2O₂ x2
<em>2Al₂O₃⇒ 4Al+3O₂</em>
Volume of the metal = change in volume reading
Volume = 37.4 - 33
Volume = 4.4 ml
Density = mass / volume
Density = 7.101 / 4.4
Density = 1.61 g/ml
Answer:
60 g/L is the final concentration of NaI solution .
Explanation:
Molarity of NaI solution before evaporation =
Volume of NaI solution before evaporation =
Molarity of NaI solution after evaporation =
Volume of NaI solution after evaporation =
( dilution)

Molar mass of NaI = 150 g/mol
Concentration of NaI after evaporation :
0.4 M × 150 g/mol = 60 g/L
60 g/L is the final concentration of NaI solution .
Answer:
Option A. (Be)
Explanation:
Beryllium is used in alloys with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes and non-sparking tools.