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สารละลายมี pH เท่ากับ 3 จะเรียกว่าอย่างไร

1. Aเป็นกรด
2. Bเป็นเบส
3. Cอิ่มตัว
4. Dเป็นกลาง

What does the coefficient 3 in "3H₂O" mean?

1. AWater has a charge of 3
2. BEach molecule of water contains three hydrogen atoms
3. CThere are three molecules (or moles) of water
4. DEach water molecule has three oxygen atoms

What is a single covalent bond?

1. AOne electron transferred from one atom to another
2. BOne pair of electrons shared between two atoms
3. CThe attraction between two oppositely charged ions
4. DTwo pairs of electrons shared between two atoms

How does a mixture of iron filings and sulfur powder differ from the compound iron sulfide?

1. AThe compound keeps the magnetic properties of iron
2. BThe mixture has a fixed ratio of iron to sulfur
3. CThe mixture can be separated physically, for example with a magnet
4. DThe mixture is formed by a chemical reaction between the two elements

Oxygen has 8 electrons. What is its electron configuration?

1. A1s² 2s² 2p⁴
2. B1s² 2s⁶
3. C1s² 2s² 2p⁶
4. D1s² 2p⁶

เจือจางสารละลาย 2 M ปริมาตร 100 mL จนมีปริมาตรรวม 400 mL ความเข้มข้นใหม่เป็นเท่าใด

1. A0.5 M
2. B2 M
3. C1 M
4. D8 M

Why is it easier to remove the outer electron from a potassium atom than from a lithium atom?

1. APotassium has fewer protons, so its nucleus pulls much more weakly on every electron
2. BLithium has more electron shells than potassium
3. CPotassium's outer electron is in a full shell
4. DPotassium's outer electron is farther from the nucleus and more shielded by inner electrons

Why does a burn from steam at 100 °C usually cause more damage than one from liquid water at 100 °C?

1. ASteam particles are hotter than water particles at the same reading
2. BSteam releases a large amount of extra energy as it condenses on the skin
3. CLiquid water cannot pass any of its heat to the skin
4. DSteam carries dissolved acid that damages the skin