Trong tự nhiên, magnesium có 3 đồng vị bền là ²⁴Mg, ²⁵Mg và ²⁶Mg. Phương pháp phổ khối lượng xác nhận đồng vị ²⁶Mg chiếm tỉ lệ phần trăm số nguyên tử là 11%. Biết rằng nguyên tử khối trung bình của Mg là 24,32. Tính % số nguyên tử của đồng vị ²⁴Mg và ²⁵Mg.

1. % ²⁴Mg = %.

Cho hàm số \(y=f(x)\) xác định, liên tục trên \(\mathbb{R}\) và có bảng biến thiên như sau:

So sánh nào dưới đây là đúng?

Hành trình đến nhà Nữ thần Mặt Trời của Đăm Săn như thế nào?

Read the following passage about Renewable energy sources 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.

          [I] Renewable energy sources, such as solar, wind, and hydroelectric power, have gained global popularity as a sustainable alternative to fossil fuels. [II] Unlike coal and oil, renewable energy generates electricity without releasing harmful emissions, making it a cleaner option for the environment (Jacobson et al., 2017). [III] However, despite the advantages of renewable energy, there are still notable challenges that need to be addressed for it to fully replace traditional energy sources (Ell Abban et al., 2014). [IV]

          One major advantage of renewable energy is its sustainability. Renewable resources, unlike fossil fuels, are naturally replenished and do not deplete over time. For instance, solar power harnesses energy from sunlight, which is virtually endless. In addition, renewable energy contributes to reducing greenhouse gas emissions, which helps combat climate change. Many countries are increasingly investing in renewable technologies to decrease their carbon footprint and meet international climate goals.

          However, renewable energy has certain limitations. One significant issue is its intermittent nature; for example, solar and wind power depend on weather conditions, making it difficult to generate a consistent power supply. This variability can disrupt the energy grid, which relies on a steady supply of electricity to meet demand. Another challenge is the high initial cost of setting up renewable energy facilities. Although prices have decreased in recent years, installing solar panels or wind turbines still requires substantial upfront investment (IRENA, 2019).

          Despite these challenges, advancements in technology are gradually making renewable energy more efficient and accessible. Improved energy storage systems, such as batteries, allow excess power generated during favourable conditions to be stored and used later, ensuring a more reliable energy supply. As technology and infrastructure improve, renewable energy may eventually.

The word "it" in paragraph 1 refers to ____.

Trong mp tọa độ Oxy, cho đường tròn lượng giác. M thuộc đường tròn sao cho \(\widehat{AOM}=\frac{\pi }{6}\) (M thuộc góc phần tư thứ tư). Số đo \(\overset{\curvearrowright }{\mathop{AM}}\,\) có thể là giá trị nào?

Em hãy cho biết những nhận định sau đây là không đúng khi bàn về chức năng của giá cả thị trường? 

Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanks from 7 to 12.

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 ___(7)___ 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 ___(8)___ the most important tasks first.

● Break down big projects! Tackling a large project can be daunting, but breaking it into smaller, manageable parts helps ___(9)___ progress without feeling overwhelmed.

● Avoid distractions! ___(10)___ multitasking, focus on one task at a time to ___(11)___ your efficiency.

● Take breaks! Give yourself regular breaks to rest and recharge, which can help maintain a higher ___(12)___ of productivity.

Nhà nước ở Hy Lạp thời cổ đại được tổ chức theo hình thức nào sau đây?

Tập hợp các quy phạm pháp luật có đặc tính chung để điều chỉnh các quan hệ xã hội trong một lĩnh vực nhất định của đời sống xã hội gọi là gì?

Một người đạp xe quãng đường 2 km từ nhà đến siêu thị trong 10 phút, rồi từ siêu thị đến hiệu sách cách đó 3 km trong 18 phút. Tốc độ trung bình của người đó trên cả quãng đường là

Vì sao trong thời cổ đại người Ai Cập thạo về hình học?

Nước và muối khoáng được vận chuyển từ đất vào rễ theo gian bào thì tại bộ phận nào, hoạt động này buộc phải chuyển sang con đường tế bào chất?

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.

STAY SAFE: UNDERSTANDING SCAMS AND HOW TO PREVENT THEM

What is a scam?

A scam is a deceptive scheme delivered through digital communications with the intent to steal money or personal information. These schemes take many forms, including online fraud, phishing emails, and fake lotteries. In (7) _____ words, scams are tricks that prey on your trust and can lead to significant financial loss.

Common types of scams

-          Phishing: fraudulent emails or messages that appear to be from legitimate sources, tricking you into (8) _____ personal information.

-          Lottery scams: notifications claiming you’ve won a (9) _____, requiring you to pay a fee to claim it.

-          Other scams: these can include fake charities, advance-fee scams, and online auction fraud, each designed to exploit individuals in different ways.

Tips to prevent scams

-          Verify sources: always check the (10) ____ of requestions for personal information.

-          Root out suspicious communications: don’t engage with unknown contacts and report any suspicious emails or calls to the authorities (11) _____ potential scams.

-          Protect your information: use strong passwords and enable two-factor authentication on your accounts to add an extra (12) ______ of security.

Tam giác ABC có AB = 4, BC = 6, \(AC = 2\sqrt 7 \). Điểm M thuộc đoạn BC sao cho MC = 2MB. Tính độ dài cạnh AM. 

Cho dãy số \(\left(u_{n}\right)\) biết \(\left\{\begin{array}{l}u_{1}=1 \\ u_{n}=\frac{1}{3} u_{n-1}+2\end{array}\right.\). Mệnh đề nào sau đây đúng?

Ngành công nghiệp truyền thống của Liên bang Nga là gì?

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.

Fire Ant Festival 2024 - November 25

The upcoming Fire Ant Festival will be an incredibly exciting event, where you will be introduced (1)______ lively games and thrilling activities. In a vibrantly decorated outdoor space, visitors will have the chance to take part in traditional games such as tug-of-war, endurance competitions, and on-land boat racing. The highlight of the festival is the (2)______, where teams will compete to create (3)______ fire ant-inspired structures. Additionally, guests can enjoy breathtaking fire dance performances (4)______ by professional artists from various regions. Although named after a creature known to(5)______ a threat to many other species, the festival has proven to be safe for visitors. The festival is also an opportunity for visitors to try unique traditional folk games, which have been preserved and developed over many generations. Come join us to soak up the lively atmosphere, we promise(6)____ you unforgettable memories! 

Mark the letter A, B, C or D to indicate the best arrangement of utterances or sentences to make a meaningful exchange or text in each of thefollowing questions from 25 to 29. 

a. Mai: Nam, I’d like to introduce you to Alan Samson, our newcomer from Australia.

b. Alan: Hi, nice to meet you too.

c. Nam:  Hi, Alan! It’s my pleasure to meet you.