Combined Science — Chemistry Flashcards
6 cards from real O-LEVEL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Combined Science — Chemistry flashcards as text
What is the number of protons in an atom called?
Answer: Atomic number
The atomic number is the number of protons in the nucleus of an atom, and it defines the element.
Which property of metals explains why they can be drawn into wires?
Answer: Ductility
Ductility is the property that allows metals to be drawn into thin wires without breaking.
What type of reaction is: CH₄ + 2O₂ → CO₂ + 2H₂O?
Answer: Combustion
This is a combustion reaction — methane (CH₄) burns in oxygen to produce carbon dioxide and water.
What is the name of CaCO₃?
Answer: Calcium carbonate
CaCO₃ is calcium carbonate, commonly found in limestone, marble, and chalk.
Which gas is produced at the cathode during electrolysis of dilute sulfuric acid?
Answer: Hydrogen
During electrolysis of dilute sulfuric acid, hydrogen gas is produced at the cathode (negative electrode) as H⁺ ions are reduced.
What is the purpose of a catalyst in a chemical reaction?
Answer: To provide an alternative pathway with lower activation energy
A catalyst provides an alternative reaction pathway with lower activation energy, speeding up the reaction without being consumed.
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