\(a) Ca + 2H_2O \to Ca(OH)_2 + H_2\\ CaO + H_2O \to Ca(OH)_2\\ n_{Ca} = n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)\\ m_{Ca} = 0,15.40 = 6(gam)\\ \Rightarrow m_{CaO} = 17,2 - 6 = 11,2(gam)\\ b) n_{Ca(OH)_2} = n_{Ca} + n_{CaO} = 0,15 + \dfrac{11,2}{56} = 0,35(mol)\\ m_{Ca(OH)_2} = 0,35.74 = 25,9(gam)\)

\(=>5.4200\left(t2-35\right)=315000=>t2=50^OC\)

REFER

The flower race on the river in my hometown is held in the first spring of the year. Today, the sky is clear. Hundreds of flowers race each other to bloom under the warm sun. People went to see the festival in large numbers. The two sides of Tra Giang River are bustling. Everyone is looking forward to the race. The racing boats are beautifully decorated, so are the flags. The operators on the boat were strong, muscular and agile guys. When hearing the whistle-blowing effect of the organizers, everyone turned their eyes forward. When receiving the "start" command, the Ao Dai rushes quickly, the riders are quick, non-stop. Water splashed, drums urged “Tung! Tung! Tung "resounds. The audience cheered with applause. Laughter, voices calling each other make the festival scene very lively.

THAM KHẢO:

Halloween is a holiday celebrated on October 31st. The most common colors of the day are orange and black. Halloween comes from the ancient Celtic festival Samhain. The ancient Celts believed that on October 31st, now known as Halloween, the boundary between the living and the deceased is not clear, and the dead become dangerous for the living by causing problems such as sickness or damaged crops. On Halloween, the ancient Celts would place a skeleton by their window to represent the dead. Believing that the head was the most powerful part of the body, containing the spirit and knowledge, the Celts used the "head" of the vegetable to decorate their houses. On this day people often wear strange clothes as characters in horrible novels or movies to frighten others. People usually like to dress as ghosts, skeletons, or witches. Now Halloween is an official holiday in almost all European countries.

^_refer

^{_{Halloween is a holiday celebrated on October 31st. The most common colors of the day are orange and black. Halloween comes from the ancient Celtic festival Samhain. The ancient Celts believed that on October 31st, now known as Halloween, the boundary between the living and the deceased is not clear, and the dead become dangerous for the living by causing problems such as sickness or damaged crops. On Halloween, the ancient Celts would place a skeleton by their window to represent the dead. Believing that the head was the most powerful part of the body, containing the spirit and knowledge, the Celts used the "head" of the vegetable to decorate their houses. On this day people often wear strange clothes as characters in horrible novels or movies to frighten others. People usually like to dress as ghosts, skeletons, or witches. Now Halloween is an official holiday in almost all European countries.}}

General conversation between old friends

John:-  Hello peter, I haven't seen your brother in almost ten years. What's he doing with himself?
Peter:- He's not doing anything at the moment he's not doing too well.
John:-  I am so sorry to hear that what's the matter with him?
Peter:- Well about six years ago, he started to complain that he was weak all the time.
John:-  So what is it due to? Old age or is he sick.
Peter:- I think it is a mixture of both. We have been to many doctor's and they can't find anything wrong with him. He thinks it is because when he was younger he didn't take care of himself.
John:-  That makes a lot of sense. I have always tried to live a healthy lifestyle since I was young.
Peter:- That's what my brother tells me now every time I see him.
John:-  Well, please tell him I was asking about him and he starts feeling better.
Peter:- Thanks John. I'll pass on your regards to him when I see him next.

topic1

1.Walk or ride your bike whenever possible. One of the best things you can do to help stop pollution is to stop using your car for short trips. If the weather is nice and you don’t have too far to go, consider walking or riding your bike. You will help reduce air pollution and you will get some exercise and fresh air in the process

2.Use public transportation. Riding the bus, train, or subway is another great way to avoid using your personal vehicle and reduce carbon emissions. If you have access to good public transportation where you live, take advantage of it. Since you won’t have to worry about keeping your eyes on the road, you can take advantage of the time to read, catch up on news, or just relax.

số các số hạng là:(|100|-|-1|):1+1=100(số hạng)

chia tổng đó thành 50 nhóm

(-1)+2+ (-3)+4+...+(-99) +100

=[(-1)+2]+[(-3)+4]+...+[(-99)+100]

=1+1+.....+1

=1.50=50