解析 C。解析:化学变化是产生新物质的变化。A 改变物质颜色可能是物理变化,如颜料混合。B 冰融化是物理变化,状态改变。C 燃烧木材产生新物质,是化学变化。D 压扁易拉罐是物理变化,形状改变。本题考查对化学变化概念的理解,涉及词汇有 chemical change(化学变化)、substance(物质)等。
A. the wax changes its shape in melting but new substances are formed in burning B. burning is always a chemical change and melting is always a physical change C. the wick disappears in burning but the wax remains in melting D. physical changes are reversible and chemical changes are irreve...
百度试题 结果1 题目Which of the following is an example of a chemical change? A. Melting ice B. Breaking a glass C. Burning wood D. Folding a paper 相关知识点: 试题来源: 解析 C。燃烧木材会产生新的物质,属于化学变化。反馈 收藏
What is the process of melting and freezing? Melting is the process of turning a solid into a liquid. Freezing is the process of turning a liquid into a solid.Physical Changes There are two types of changes that a substance can undergo. A chemical change is a change that results in an ...
melts the under side of the ice, at the same time that it is melting it more directly above, making it uneven, and causing the air bubbles which it contains to extend themselves upward and downward until it is completely honeycombed, and at last disappears suddenly in a single spring rain...
Arc melting is a process used in the manufacture of titanium alloy ingots and castings, involving methods such as vacuum-arc remelting (VAR), induction-skull melting (ISM), and plasma arc melting (PAM). It offers advantages like improved flexibility in ingot size and shape, better control over...
Why is melting of ice at 0 degrees Celsius a reversible process? If 1 mol of ice melts at its melting point of 273 K, the entropy change for the ice is 22.0 J/K. If the ice melts in someone s hand at 34 degrees C, what is the change in the entropy o...
Melting point, temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature will increase until the melting point is reached. More heat then will convert the solid into a liq
The results show that the composition change during melting is mainly attributed to chemical reactions between phosphorus and halogens (fluorine and/or bromine) and/or oxygen. When a sample contains high phosphorus and low fluorine content, the losses of bromine and phosphorus are dominant. When a...
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