您所在的当前位置：初中化学试题 >

元素的质量分数计算

> 人体缺乏维生素C（简写为Vc）就会患坏血病．如图为某品牌维生素C片说明书的一部分．根据信息进行的下列计算，不正确的是（　　） A．每片含Vc质量为10mg B．Vc中碳元素质量分数为30% C．Vc中碳、氢和氧三种元素质量比为9﹕1﹕12 D．若成人每天对Vc的最低需要量为60mg，每天可服用该品牌维生素C片3次

问题：

发布时间：2024-09-10

人体缺乏维生素C（简写为Vc）就会患坏血病．如图为某品牌维生素C片说明书的一部分．根据信息进行的下列计算，不正确的是（　　）

A．每片含Vc质量为10mg

B．Vc中碳元素质量分数为30%

C．Vc中碳、氢和氧三种元素质量比为9﹕1﹕12

D．若成人每天对Vc的最低需要量为60mg，每天可服用该品牌维生素C片3次

参考答案：

提问用户：H7***cul

可能感兴趣的题目：

1 一首全世界无产阶级的革命战歌被人们经久传唱，这就是著名的 [ ] A．《神曲》 B．《命运交响曲》 C．《英雄交响曲》 D．《国际歌》
2 诚信，是我们踏上社会的第一步。“现代社会是讲诚信的社会，诚信周围是诚信人，不诚信周围是不诚信的人，我们首先自己要做一个诚信的人，才能要求别人讲诚信。”我们每一个人，不管是现在在学校生活还是今后踏上社会，都应该以实际行动，从我做起，“守时”、“守诺”，“量力而行，不轻易许诺”，这是一个人有责任心的体现，更是我们今后立足社会、创造财富的无形资本。（1）你理解的诚信是什么？ _______________________________________________________________________________ （2）结合材料说明为什么我们要坚守诚信？ _______________________________________________________________________________ （3）为在校园宣传诚信，拟写三条宣传诚信的标语。 _______________________________________________________________________________
3 有盐酸和MgCl 2的混合溶液100g，向混合溶液中逐滴加入溶质质量分数为10%的NaOH溶液，生成的沉淀与加入的10%的NaOH溶液质量关系如图所示．若MgCl 2在混合溶液中质量分数为9.5%．求：（1）A点处溶液中的溶质化学式为______．（2）恰好沉淀完全时，所得溶液中溶质的质量分数是多少？（结果精确到0.1%）______ （3）C点的坐标（x 1，y 1）中为______．
4 阅读理解。根据其内容回答问题。 In almost every big university in the United States, football is a favorite sport. American football is different. Players sometimes kick (踢) the ball that is oval (not round), but they also throw the ball with their hands and run with it. They try to take it to the other end of the field. They have four chances to move the ball ten yards (长度单位,码). They can carry it or they can throw it. If they move the ball ten yards, they can try to move it another ten yards. If they move it to the end of the field, they receive six points (点,分). It is difficult to move the ball. Eleven men on the other team try to stop the man with the ball. If he does not move the ball ten yards, his team kicks the ball to the other team. Each university wants its own team to win. Many, many people come to watch. They all shout for their favorite team. Young men and women come on the field to help the people shout more. They dance and jump while they shout. Each team plays ten or eleven games each season. The season begins in September and ends in November. If a team is very good, it may play another game after the season ends. The best teams play again on January1, the first day of the New Year. Many people go to see these games and many others watch them on TV. 1. What does this passage (短文) talk about? _____________________ 2. Do people in the United States like football very much? _____________________ 3. How many players are there in an American football team? _____________________ 4. Is it easy or difficult to move the ball? _____________________ 5. What are the features (特点) of American football? _____________________
5 为什么无性生殖的后代，个体之间十分相像呢？这与染色体和基因在亲子代间的传递状况有关吗？
6 某同学在“探究平面镜成像特点”的实验中，取两段等长的蜡烛A和B，点燃玻璃板前的蜡烛A，观察玻璃板后的像，如图所示：（1）平面镜成像的原理是______；（2）点燃蜡烛A，小心地移动蜡烛B，直到与蜡烛A的像完全重合为止，这样做的目的既确定了像的位置又验证了______；（3）移去蜡烛B，并在其所在位置上放一光屏，则光屏______（选填“能”或“不能”）承接到蜡烛A的烛焰的像；（4）做完实验后某同学总结了一些关于平面镜成像的知识，其中不准确的是______ A．将蜡烛向玻璃板靠近，像的大小不变 B．将蜡烛和像所在的位置用直线连接，连线跟玻璃板垂直 C．当蜡烛与玻璃板的距离为10cm时，像和物相距20cm D．将玻璃板换成平面镜，成像更清晰，更有利于进行成像特点的探究．
7 【题文】This music ________ great. A．listen B．listens C．sounds D．sound
8 改错。 Mr and Mrs Peter don"t go out in the evening. But last night, Mrs Peter said to his husband, "There is an good film at the cinema this evening. Can we go and seeing it?" Mr Peter was such happy about it that he went there with his wife. They both enjoyed the films. They didn"t get home until the film was over in eleven o"clock. On their way home they saw a woman run along the road very fast and a man running after her. Mr Peter drove the car slow near the woman and said to her, "Can we help you?" "No, thank you." The woman said but she doesn"t stop running. "My husband or I always run home after the cinema. and the last one washes the bowls at home." 1. _____ 2. _____ 3. _____ 4. _____ 5. _____ 6. _____ 7. _____ 8. _____ 9. _____ 10. _____
9 根据你对课文的理解，回答下列问题： (1) “会当凌绝顶，一览众山小”表现了什么样的人生哲理？ ____________________________________________________ (2)《戴震难师》表现了少年戴震的什么精神？ ____________________________________________________
10 急救知识是遇到突发病人时的一些常识，当你遇到人突然晕倒时，下列哪一种紧急求助的方法你认为最为合适（） A．拨打“120”，等待急救车到来。 B．马上采取急救措施 C．先拨打“110”，在急救车到来前，先采取一些必要的救治措施 D．先拨打“120”，在急救车到来前，先采取一些必要的救治措施