Classification of Matter

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이 개념을 다룬 실제 CSCA 기출문제입니다. 답을 펼치기 전에 먼저 직접 풀어 보세요.

1. CSCA Chemistry December 2025 Past Paper
   Which of the following substances is a pure substance? ( )
   • A. Hydrochloric acid solution
   • B. A mixture of ice and water
   • C. Air
   • D. Saturated sodium chloride solution
   정답 및 풀이 보기

   정답: B

   Answer: B A pure substance contains only one substance. A mixture of ice and water has a solid and a liquid phase, but both are H₂O, so it is a pure substance. Hydrochloric acid, air and saturated salt solution all contain several components and are mixtures.
   CSCA Chemistry December 2025 Past Paper 전체에서 보기
2. CSCA Chemistry April 2026 Past Paper
   Which of the following changes is a chemical change? ( )
   • A. Complete combustion of carbon
   • B. Crushing paper
   • C. Freezing of water
   • D. Evaporation of alcohol
   정답 및 풀이 보기

   정답: A

   Answer: A Carbon undergoes complete combustion to form carbon dioxide - a new substance is produced, so it is a chemical change; the others are physical changes.
   CSCA Chemistry April 2026 Past Paper 전체 풀기 — 시간 측정 및 채점
3. CSCA Chemistry March 2026 Past Paper
   Which everyday phenomenon involves a chemical change？
   • A．Refrigerator cooling
   • B．Rusting of an iron pot
   • C．Glass breaking
   • D．Evaporation of alcohol
   정답 및 풀이 보기

   정답: B

   Chemical change produces new substances. A/C/D are physical. B: Iron rusting = $\mathrm { Fe } + \mathrm { O } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { O } \rightarrow \mathrm { Fe } _ { 2 } \mathrm { O } _ { 3 } \cdot \times \mathrm { H } _ { 2 } \mathrm { O }$. Answer: B．
   CSCA Chemistry March 2026 Past Paper 전체 풀기 — 시간 측정 및 채점