18 Questions
What is the first step in balancing a chemical equation?
Check the number of atoms of each element on the reactants and products side
In the equation Fe + 4(H2O) ⟶ Fe3O4 + 4(H2), how many hydrogen atoms are there on the products side?
8
Which of the following equations is already balanced according to the text?
CO(g) + O2(g) ⟶ CO2(g)
What type of reaction is represented by the equation Al + H2SO4 ⟶ AL2(S04)3 + H2?
Combination reaction
In the equation 4Zn + 10HNO3 ⟶ 4Zn(NO3)2 + 5H2O + N2O, how many molecules of water (H2O) are produced?
5
What is the last step in balancing the equation Fe + 4(H2O) ⟶ Fe3O4 + 4(H2)?
Balancing Fe by multiplying by 3 on LHS
What is the black substance formed when silver articles turn black after reacting with hydrogen sulphide?
Silver sulphide
Which phenomenon is involved when silver articles develop a black layer over time?
Corrosion of silver
What type of decomposition reaction requires energy in the form of heat to break down the reactants?
Thermal decomposition reaction
In a decomposition reaction requiring light energy, what type of energy-driven reaction is it known as?
Photochemical decomposition reaction
Which compound decomposes into calcium oxide and carbon dioxide when heat energy is supplied?
CaCO3
What products are formed when the electrolytic decomposition of water occurs?
$H_2$ and $O_2$
What is the primary reason for using nitrogen gas instead of air to pack food items like potato wafers?
To prevent oxidation of fats and oils
How does rancidity impact food items?
It results in a foul taste and smell
Why is it recommended to avoid keeping cooked food and food materials in direct sunlight?
To prevent rancidity
Which metal object is particularly susceptible to damage caused by environment factors like oxidation?
Iron railing
What is the color change observed when iron nails are dipped in copper sulphate solution for 30 minutes?
Brownish for iron nails, light green for copper sulphate solution
Why is respiration classified as an exothermic process?
Energy is released during respiration
Learn how to balance chemical equations step-by-step with this detailed guide. Practice balancing equations like Fe + H2O ⟶ Fe3O4 + H2 with clear explanations for each step.
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