题干

下列说法正确的是

A:化学键的变化必然会引起能量变化,所以,能量变化也一定会引起化学变化

B:所有化学变化的能量都可以通过原电池转化为电能

C:所有化学变化一定遵循质量守恒和能量守恒

D:化学变化一定会引起物质种类的变化,所以体系内物质种类变化一定发生了化学变化

上一题 下一题 0.0难度 选择题 更新时间:2019-10-20 09:43:50

答案(点此获取答案解析)

C

同类题2

阅读下面短文,从短文后各题所给的四个选项(A、B、C、D)中,选出可以填入空白处的最佳选项

      A gentle breeze blew through Jennifer's hair. The golden red sunwas1. She was on the beach, looking up at the fiery(火红的)ball. She was 2by its color, deep red in the middle, softly fading into yellow. She could hear nothing but the waves and these agulls 3up above in the sky.

      The atmosphere4 her. After all she had been through, this was what she needed. “It's getting 5,”she thought, “I must go home. My parents will be6where I am.” She wondered how her parents would 7,   whenshe got home after the three days she was8. She kept on walking, 9herself to the bungalow(小房子) where she spent every summer holiday. The road was deserted. She walked slowly and 10 . Just in a few hundred meters she would besafe in her house.

      It was really getting dark now. The sun had set a few minutes before and it was getting cold, too. She 11she had her favorite sweater on — it kept herreally warm. She imagined having it 12her. This thought disappeared when she finally saw her front door. It seemed 13. The outside garden seemed 14. She was shocked: her father was usually so strict about keeping everything clean and tidy.

      She entered the house. First, she went into the kitchen whereshe saw a 15 written by her father. It said, “Ellen, thereis some coffee16I went looking.” Ellen was her mother but — wherewas she?  She entered her parent's home.Then she saw her. Her mother, lying on the bed, 17. Jennifer would have wanted to wake her up but she looked too tired. So Jennifer just fell asleep beside her. When Jennifer 18, something was different. She was in her cozy bed in her pajamas.

      It felt so good being back home.19she heard a voice, “Are you feeling better now? You know you got us very, very 20.”