Đáp án:
Tóm tắt:
`t_1=25^oC`
`t=100^oC`
`Q=787,5kJ=787500J`
`c=4200J//kg.K`
`V=?`
Giải:
Nhiệt lượng nước thu vào để sôi là:
`Q=m.c.(t-t_1)`
`⇔787500=m.4200.(100-25)`
`⇔787500=315000m`
`⇔m=2,5 (kg)`
`⇒V=2,5` (lít)
Vậy: thể tích nước trong bình là `2,5` lít
`2,5l`
Giải thích các bước giải:
Có `Q = 787,5kJ = 787500J`
Vì nước sôi `-> 100^oC`
Nên có : `Q = mC ΔT = m . 4200 . ( 100 - 25)`
`=> m = 2,5 (kg)`
Thể tích nước trong bình là :
`V = m/D =` 2,5/1`= 2,5(lít)`
47. The issues which have been considered in the previous section (allow/allows) us to speculate on problems that learners might encounter 48. An early analysis of the results (show/shows) that the Socialists have won. 49. The number of students who knew the answer to the last question on the exam (was/were) very low. 50. The United States of America (consists/consist) of 50 separate states. 51. The view of these disciplines (vary/varies) from time to time. 52. The actress, along with her manager,( is/are) going to the party tonight. 53. It was the speaker, not his ideas, that (has/ have) provoked the students to riot. 54. The country’s first general election since it won independence (is/are) to be held next month 55. Mr. Robinson, accompanied by his wife and children, (is/are) arriving tonight. 56. Neither the boys nor Carmen (have/has) seen the film before. 57. John, bringing his girlfriend to see me, (has/have) just arrived. 58. The majority (believe/believes) that we are in no danger. 59. Neither of the French athletes (have,has) won this year 60. Nobody but Ted and Bill (was/were) eager to help 61. Not John but you (was/were) responsible for the error 62. A lot of the pollution (is/are) caused by the paper factory on the edge of the town 63. The secretary and accountant of the company (have/has ) not come yet. 64. Twenty five dollars (seem, seems) too much to pay for this book. 65. To my opinion, living in happiness for 10 years (is/are) not a long time. 66. Physics (study/ studies) mechanics, heat, light, sound and electricity. 67. His silence (mean/ means) that he agrees with us.
Ai có thủ thuật làm bài đồng nghĩa chỉ cho đi (trừ học hết từ điển nhé
trong như tiếng hạc bay qua đục như tiếng suối mới sa nửa vời sử dụng biện pháp nghệ thuật nào nêu tác dụng
a.famous b.asleep c,preety d.careful khoanh câu có trọng âm khác
mọi người giúp mik vs mik cần gấp
Cần người giúp nốt 10 câu trắc nghiệm này, em chỉ cần đáp án chính xác, không cần chi tiết đâu ạ
Question 1: John doesn't speak English _____________ Peter. A. as well B. as better as C. as well as D. so good as Question 2: The garden looks since _____________ you tidy it up. A. better B. well C. gooder D. as good as Question 3: This one is prettier, but it costs _____________ as that one. A. as much as B. twice as much C. as many D. twice as many Question 4: The house over there is _____________ building in the city. A. the oldest B. the eldest C. older than D. as old as Question 5: Mr David doesn't work here_____________. He left about six months ago A. any more B. any longer C. no longer D. A and B Question 6: I'm sorry I'm late. I got here _________ as I could. A. as fastly B. as fast C. as faster D. so fast Question 7: Your English is improving. It is getting __________ A. good B. well C. better D.good and well Question 8: Ann works __________ than most of her friends. A. harder B. a lot more hardly C. more hardly D. many harder Question 9: You must explain your problems ___________ A. as clear as you can B. as clear as you are C. as clearly as you can D. as clearly as you are Question 10: Nam is __________ student in his class. A. the best B. better C. the good D. best Question 11: John is______________ of the boys. A. taller than B. so tall as C. the tallest D. the most tall Question 12: Jane is not ______________ her brother A. more intelligent as B. so intelligent as C. intelligent as D. so intelligent that Question 13: It is a long journey by train. It is much _______ by road. A. quickly B. more quickly C. quick D. quicker Question 14: Commercial centres are __________ they were many years ago. A. as popular as B. more popular C. most popular D. not as popular as Question 15: The sooner, the ________ A. better B. best C. good D.more good Question 16: It's _______ film I have ever watched. A. best boring B. most boring C. the best boring D. the most boring Question 17: These days, _______people are learning English. A. much and more B. many and many C. more and more D. many and much Question 18: I've never had a ________ meal than that. A. more delicious B. the more delicious C. deliciouser D. most delicious Question 19: This shirt is too small. I need a ________ size. A. large B. larger C. more large D. largest Question 20: Don't walk so_______ . Can't you walk_________? A. fast/slower B. fast/more slowly C. fastly/slower D. fastly/more slowly
a, -3/2 -2x + 3/4 = -2 b, (-2/3.x-3/5).(3/-2 -10/3) = 2/5
Lượng nước trong hạt tươi là 20%. Có 200 kg hạt tươi sau khi phơi khô nhẹ đi 30 kg. Tính tỉ số phần trăm nước trong hạt đã phơi khô?
phân số 2021/1000 viết dưới dạng số thập phân là
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến