A. decomposition. B. synthesis. C. combustion. D. neutralization. 相关知识点: 试题来源: 解析 B。解析:两种物质结合形成新物质的过程叫做合成。选项 A 分解是一种物质分解成多种物质。选项 C 燃烧是物质与氧气发生剧烈反应。选项 D 中和是酸和碱反应生成盐和水。反馈 收藏 ...
This is called___. A. physical change B. chemical combination C. melting D. boiling 相关知识点: 试题来源: 解析 B。解析:两种物质结合形成新物质叫做化学结合。选项 A 物理变化不符合;选项 C 融化是物理变化;选项 D 沸腾也是物理变化。反馈 收藏 ...
A. occur B. occurs C. occurred D. occurring 相关知识点: 试题来源: 解析 B。解析:根据条件状语从句的时态规则,主句是一般将来时,从句要用一般现在时。a chemical reaction是第三人称单数,occur要变为occurs。A选项occur没有使用第三人称单数形式,C选项occurred是一般过去式,D选项occurring是现在分词,不能作谓...
The substancesthat undergo changes in chemical reaction are called the ,and the new substancesformed are the .如何将EXCEL生成题库手机刷题 如何制作自己的在线小题库 > 手机使用 分享 反馈 收藏 举报 参考答案: reactants products 复制 纠错举一反三 1851 年的伦敦博览会是英国展出最新工业成果的盛会,它...
For years it has been generally acknowledged that OA is a physical process, i.e., particle alignments and interface fusion via mass diffusion, not involving the formation of new substances. Hence, the obtained crystals maintain identical crystallographic structures and chemical constituents to those ...
Observations of a Chemical Change Reactants and Products In chemical reactions, we start with The Reactants are the substances. The Products are the substances which result from the chemical reaction. Basic format of chemical equation:
All physical objects radiate in response to incident electromagnetic waves that are always present in the environment. The spectrum emitted by simple objects such as particles, atoms, molecules and chemical substances, can be recorded and studied much easier than that of complex dynamical systems...
Moreover, given the current environmental problems, these substances have non-toxic appearances, in addition to being easily dissolved in the test solution, thereby enhancing their effectiveness in providing protection. Several organic compounds containing "N" have been commonly referred to in the ...
A chemist from RUDN University has created a series of catalysts for click chemistry. These reactions are widely used in the synthesis of biologically active substances, as well as in biological and medical research. New catalysts produce a yield of 99 percent. They are based on cyclodextrin and...
Fertility in birds is dependent on their ability to store adequate populations of viable sperm for extended durations in sperm storage tubules (SSTs). The exact mechanisms by which sperm enter, reside, and egress from the SSTs are still controversial. Sharkasi chicken sperm showed a high tendency...