Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
- Làm mềm nước cứng: $Na_2CO_3$ kết tủa các ion $Ca^{2+}$ và $Mg^{2+}$ gây ra tính cứng của nước.
- Sản xuất thủy tinh, xà phòng, chất tẩy rửa.
- Trong công nghiệp dệt, giấy.
- Sản xuất sodium hydrogencarbonate ($NaHCO_3$).
Câu hỏi liên quan
Read the following advertisement and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 1 to 6.
Biosphere 2025: Where Your Home Breathes With The Planet
The people (1)_________ in Biosphere homes report improved health and lower utility bills. Never (2)_________ off until tomorrow what you can do today for our planet!
Visit our showroom (3)_________ how Biosphere technology can transform your home. Our (4)_________ system removes 99.9% of pollutants while connecting to your smartphone.
We handed customers (5)_________ to our specialists for personalized consultations. (6)_________ design your space with eco-friendly materials that last for generations.
Biosphere 2025 - Your home's natural connection to Earth!
Limited time offer: 15% discount on all smart home installations before June 30th!
Website: www.biosphere2025.com
Call: (555) 987-6543
Email: connect@biosphere2025.com
Công dân cần có trách nhiệm gì trong việc thực hiện quyền được bảo đảm an toàn và bí mật thư tín, điện thoại, điện tín của công dân?
Cấp độ tổ chức sống nào sau đây được xem là cấp độ tổ chức sống cơ bản nhất?
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of the numbered blanks from 24 to 28.
Doing chores is good for children. Kids (24) _______ do housework develop important life skills that they will need for the rest of their lives. Doing the laundry, cleaning the house, and taking care of others are among the important skills students will need when they start their own families. These are the things that schools cannot fully teach, (25) _______ it’s important for children to learn them at home. Moreover, sharing housework helps young people learn to take (26) _______. They know that they have to try to finish their tasks even though they do not enjoy doing them. (27) _______ benefit of housework is that it helps develop children’s gratitude to their parents. When doing housework, they learn to appreciate all the hard work their parents do around the house for them. In addition, doing chores together helps (28) _______ family bonds, creating special moments between children and parents. All in all, doing housework can bring a lot of benefits to children.
(Adapted from Global Success)
Tại sao khi đo huyết áp phải tránh bị căng thẳng thần kinh, không nói chuyện, nghỉ ngơi ít phút trước khi đo nếu từ nơi khác đến?
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
Who are you?
On 6 June 2011, the media reported the kidnapping of a female Syrian-American blogger called Amina Arraf. Regarded as a daring political rebel, the 35-year-old had gained popularity for her blogs protesting the lack of freedom in Syria. Yet, only two days later, it was discovered that Amina had never existed. She was a fictional character created by Tom MacMaster, a forty-year-old American PhD student at the University of Edinburgh.
MacMaster's invention is an example of sock puppetry: the use of false identities to deceive others. (I). The false identity is known as a sock puppet, and its creator, a puppet master. (II). MacMaster created Amina to express his views on Middle Eastern affairs without offending other Americans. (III). Writing as Amina gave him the authority to say what he wanted. (IV).
At the turn of the millennium, Debbie Swenson created Kaycee Nicole, a fictional teenage girl suffering from terminal cancer. Her blog, Living Colours, described Kaycee’s struggle, attracting millions of readers. When Kaycee 'died' on 14 May 2001, her fans were devastated. Their distress turned to anger when they discovered that Kaycee was not real. Swenson had developed the character to gain attention and sympathy.
While Amina and Kaycee were used to meet their creators' needs, other identities have been invented for profit. American gun advocate John Lott made up a fake student, Mary Rosh, to defend his writing online and give him positive reviews. Mystery writer RJ Ellory fabricated a team of sock puppets to praise his own books and tear into those of his rivals. British historian Orlando Figes lost credibility when he had to publicly apologise for doing the same.
Yet none of these stories compare to large-scale sock puppetry today. The New York City Police Department has false identities on social media to catch criminals. The US military is believed to use sock puppets to track potential terrorists. It is clear that the internet is a minefield today and we all have to step very carefully in order not to get hurt.
Which of the following is NOT a reason for creating sock puppets?
Read the following leaflet and mark the option that best fits the numbered blanks from 19 to 24.
TIPS FOR BETTER TIME MANAGEMENT
Want to get more done in less time? Follow these strategies for improving your productivity and focus!
Common Struggles:
Many people (19) _____ effective time management, leading to stress and unfinished tasks. Research shows that nearly 70% of workers feel overwhelmed by their workload.
Actionable Solutions!
- Prioritize your tasks! Start by making a to-do list and (20) _____ with the most important tasks first.
- Break down big projects! Tackling a large project can be daunting, but breaking it into smaller, (21) _____ parts helps ensure progress without feeling overwhelmed.
- Avoid distractions! (22) _____ multitasking, focus on one task at a time to (23) _____ your efficiency.
- Take breaks! Give yourself regular breaks to rest and recharge, (24) _______ can help maintain a higher level of productivity.
Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.
How the Generation Gap Plays Out in the Workplace
As a recruiter, I am in constant communication with executive clients and HR colleagues. I regularly (7) ________ on candidates I’ve placed, to see how they are getting on in their new roles. Here are some of the important generational differences I see that can lead to potential (8) ________ if not properly understood:
Communication styles
• The young generation is more (9) ________, quick to offer constructive criticism, individualistic, with a more casual approach.
• Gen X values hard work and long hours, a/k/a ‘The Grind’ – they are more skeptical, formal, and uncompromising.
Leadership styles
• The young generation is extremely open-mindeD. They resist micromanagement, and resent pressure. (10) ________ factor that sets them apart is their emphasis on work-life balance.
• (11) ________, their Generation X supervisors, on the other hand, are intensely focussed on the organisational processes that brought the company success; they tend to prioritise (12) ________ and the bottom line.
Hệ thống kĩ thuật được chia làm mấy loại?
Cho hàm số \(y=f(x)\) có bảng biến thiên như hình vẽ:
Đồ thị hàm số \(y=|f(x-2001)-2019|\) có bao nhiêu điểm cực trị?
Giá trị của biểu thức \(A=\text{si}{{\text{n}}^{2}}{{15}^{\circ }}+\text{si}{{\text{n}}^{2}}{{75}^{\circ }}+\text{cos}{{120}^{\circ }}\) là
Thực hiện thí nghiệm Young về giao thoa với ánh sáng đơn sắc có bước song 0,4 mm, khoảng cách giữa hai khe là 0,5 mm, khoảng cách từ mặt phẳng chứa hai khe đến màn là 1m.
Phát biểu
Đúng
Sai
a) Trên màn quan sát hai vân sáng liên tiếp cách nhau 0,6mm.
b) Trên màn quan sát, vân sáng bậc 4 cách vân sáng trung tâm là 3,2mm.
c) Tại điểm M trên màn cách vân sáng trung tâm (chính giữa) một khoảng 5,6 mm có vân sáng bậc (thứ) 9
d) Tại điểm N trên màn cách vân sáng trung tâm (chính giữa) một khoảng 2,0 mm có vân tối thứ 2
Để có được sức cạnh tranh mạnh về kinh tế, các nước đang phát triển đã tiến hành điều nào?
Hình chiếu trục đo xiên góc cân có:
Hai điểm A và B trên cùng một bán kính của một vô lăng đang quay đều, cách nhau 20cm. Điểm A ở phía ngoài có tốc độ\({v_A} = 0,6\)m/s, còn điểm B có \({v_B} = 0,2\)m/s. Tốc độ góc của vô lăng và khoảng cách từ điểm B đến trục quay là
Nội dung nào sau đây không phản ánh đúng hậu của của lạm phát đối với đời sống xã hội?
Trong dao động điều hòa, giá trị cực đại của gia tốc là
Cho biết: So với retinal, chất diệp lục có thể được mô tả như một sắc tố có?
Loại sâu hại nào thuộc họ Muội nâu?
Một lớp có 45 học sinh. Mỗi em đều đăng ký chơi ít nhất một trong hai môn: bóng đá và bóng chuyền. Có 35 em đăng ký môn bóng đá, 15 em đăng ký môn bóng chuyền. Hỏi có bao nhiêu em đăng ký cả hai môn bóng đá và bóng chuyền?