#1
Which of the following is a chemical reaction?
Burning of wood
ExplanationCombustion involving chemical changes in wood.
#2
In atomic emission, what does the term 'emission' refer to?
Release of energy in the form of light
ExplanationEnergy release in the form of light from excited atoms.
#3
Which type of chemical reaction involves the exchange of ions between two compounds?
Double displacement reaction
ExplanationReaction where ions of reactants exchange to form new compounds.
#4
What is the stoichiometric coefficient in a balanced chemical equation?
The coefficient indicating the number of moles of reactants and products
ExplanationNumerical factor representing mole ratios in a balanced equation.
#5
Which of the following is an example of a redox reaction?
Combustion of methane (CH4)
ExplanationMethane reacts with oxygen, transferring electrons to form CO2 and H2O.
#6
What is the product of the reaction between sulfuric acid (H2SO4) and sodium hydroxide (NaOH)?
H2O + NaHSO4
ExplanationWater and sodium hydrogen sulfate are produced.
#7
Which type of reaction is represented by the general formula A + B → AB?
Synthesis reaction
ExplanationFormation of a single product from two or more reactants.
#8
What is the balanced chemical equation for the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH)?
HCl + 2NaOH → 2H2O + NaCl
ExplanationFormation of water and salt from the reaction of HCl and NaOH.
#9
In atomic emission spectroscopy, what is responsible for the unique line spectrum of each element?
Atomic structure and energy levels
ExplanationThe arrangement of electrons in atoms determines unique spectra.
#10
What is the primary purpose of a catalyst in a chemical reaction?
To lower the activation energy and speed up the reaction
ExplanationCatalysts facilitate reactions by reducing energy barriers.
#11
Which law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another?
First Law
ExplanationLaw stating the conservation of energy within a system.
#12
What is the role of a reducing agent in a redox reaction?
To lose electrons and get reduced
ExplanationSubstance that undergoes oxidation by donating electrons.
#13
Which law states that the total pressure exerted by a mixture of gases is the sum of the partial pressures of individual gases?
Dalton's Law
ExplanationLaw explaining the behavior of gas mixtures and partial pressures.