题干

如图是学校实验室从化学试剂商店买回的硫酸试剂标签上的部分内容.据此下列说法正确的是(   )

A:该硫酸试剂的物质的量浓度为18.4 mol/L

B:稀释该硫酸时应把水倒入硫酸中,边倒边搅拌

C:50 mL该H2SO4中加入足量的铜片并加热,被还原的H2SO4的物质的量为0.46 mol

D:标准状况下2.7 g Al与足量的该硫酸反应可得到H2 3.36 L

上一题 下一题 0.0难度 选择题 更新时间:2020-02-19 10:43:13

答案(点此获取答案解析)

A

同类题4

根据短文内容,选择最佳答案。

    Each summer,you hear news that some sports players are sent to hospitals because it is too hot. Our bodies can't be outside in the sun for a long time. So in hot summers,be careful about playing sports outside.

    Firstly,to play sports safely in hot weather,you must drink water. Sports drinks are great for athletes,but they have so much sugar that they'll dehydrate(使脱水)you more. However,drinking a few bottles of sports drinks will be good for you.

    Secondly,be sure to take enough breaks to let your body rest. If your coach doesn't let you take enough breaks in the heat,don't wait until you feel uncomfortable. Just be honest with your coach when you need breaks.

    Thirdly,when you have a break,don't sit in the sun. With the sun beating down on you,you'll only heat up and sweat(冒汗)more. Take a seat under a tree,or even better,go indoors for a little while. Cooling yourself down can help you stay active longer.

    Fourthly,remember that the earlier in the day you start your exercise,the cooler it will be. If you can start practice before the sun comes up,you have a few good hours to practise in the cool hours of the morning. Also,the earlier you practise,the earlier you can finish the exercise. If you need more practice time,come back to the field later in the evening,when the sun is setting.

    Last but not least,you should watch what you eat. Eat food which is high in water,starch(淀粉)and carbonhydrate(糖类),but be sure to get a good balance in your diet.

    As long as you pay attention to the above,playing sports safely in the heat isn't a difficult thing.