Classification of Matter

ข้อสอบจริงถามเรื่องนี้อย่างไร

ข้อสอบจากชุดข้อสอบ CSCA จริงที่วัดแนวคิดนี้ ลองทำเองก่อนเปิดดูคำตอบ

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
   ดูคำตอบและวิธีทำ

   คำตอบ: 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.
   ดูในชุดข้อสอบเต็ม CSCA Chemistry December 2025 Past Paper
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
   ดูคำตอบและวิธีทำ

   คำตอบ: 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.
   ทำข้อสอบเต็มชุด CSCA Chemistry April 2026 Past Paper — จับเวลาและให้คะแนน
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
   ดูคำตอบและวิธีทำ

   คำตอบ: 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．
   ทำข้อสอบเต็มชุด CSCA Chemistry March 2026 Past Paper — จับเวลาและให้คะแนน