相关试题
单选题 Which of the following is a pure substance?
单选题 The SI unit of energy is ______.
单选题 Matter is defined as anything that has mass and ______.
单选题 NaCl is a typical ______ compound.
单选题 A chemical compound is composed of two or more elements in a ______ ratio.
单选题 Ice melting into water is a ______.
单选题 A homogeneous mixture has a ______ composition.
单选题 Which of the following is a chemical change?