Classification of Matter

Как это проверяет настоящий экзамен

Задания из настоящих экзаменов CSCA по этому понятию. Решите их сами, прежде чем открывать ответ.

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
   Показать ответ и решение

   Ответ: 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.
   Открыть в полном варианте: 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
   Показать ответ и решение

   Ответ: 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.
   Решить весь CSCA Chemistry April 2026 Past Paper — на время и с оценкой
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
   Показать ответ и решение

   Ответ: 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．
   Решить весь CSCA Chemistry March 2026 Past Paper — на время и с оценкой