Chemistry Questions with Surprising Answers

Chemistry Questions with Surprising Answers

Que 1. What does it mean if a mixture is heterogeneous?
Ans 1. We can see the different parts.

Que 2. One of the essential minerals in the human body is salt. How much salt (NaCl) is in the average adult human body?
Ans 2. The average adult human body contains about 250 grams of salt, which is just over half a pound.

Que 3. What is the name of the first Noble Gas?
Ans 3. Helium.

Que 4. What is the center of an atom called?
Ans 4. Nucleus

Que 5. Only four elements are magnetic at room temperature, iron is one, the other three are.
Ans 5. Nickel (Ni), Cobalt (Co), and Gadolinium (Gd).

Que 6. Can water stay liquid below zero degrees Celsius?
Ans 6. Yes, water can stay liquid below zero degrees Celsius. First of all, the phase of material (whether it is gas, liquid, or solid) depends strongly on both its temperature and pressure. For most liquids, applying pressure raises the temperature at which the liquid freezes to solid. A solid is formed when the loose, meandering molecules of a liquid get slow enough and close enough to form stable bonds that pin them in place. When we apply pressure to a liquid, we force the molecules to get closer together. They can therefore form stable bonds and become a solid even if they have a higher temperature than the freezing point at standard pressure. But water has a little different concept we can have liquid water at sub-zero temperatures using additives. Additives such as salt can interfere with the chemical bonding needed to form a solid and, therefore, can lower water’s freezing point. Salt is composed of strong sodium and chlorine ions. When dissolved in water, the water molecules tend to stick to the salt ions instead of to each other, and they, therefore, don’t freeze as readily. As you add more salt to the water, its freezing point continues to drop until the water reaches saturation and cannot hold any more salt. If you add enough salt, the freezing point of water can be dropped as low as -21 degrees Celsius.

Que 7. If you fill a glass to the brim with ice water and the ice melts, what will happen?
Ans 7. One interesting property of water is that it achieves maximum density as a liquid, not as a solid. So, ice is less dense than water and floats. When it melts, it becomes denser. More mass per unit volume means the level of the liquid drops slightly.

Que 8. Which is the heaviest naturally occurring element?
Ans 8. Uranium.

Que 9. What is the main gas found in the air we breathe?
Ans 9. Nitrogen (around 78%)

Que 10. Which chemical element has the lowest boiling point of all the elements?
Ans 10. Helium

Chemistry Questions with Surprising Answers

Que 11. How do plants get their nitrogen from the air?
Ans 11. Plants do not get their nitrogen directly from the air. Although nitrogen is the most abundant element in the air, every nitrogen atom in the air is triple-bonded to another nitrogen atom to form molecular nitrogen, N2. This triple bond is very strong and very hard to break (it takes energy to break chemical bonds whereas energy is only released when bonds are formed). As a result, even though nitrogen in the air is very common, it is energetically unfavorable for a plant to split the nitrogen molecule in order to get the raw atoms that it can use. The strong triple bond of N2 also makes it hard for molecular nitrogen to react with most other chemicals. This is, in fact, part of the reason there is so much nitrogen in the air, to begin with. Also, the stability and symmetry of the nitrogen molecule make it hard for different nitrogen molecules to bind to each other. This property means that molecular nitrogen can be cooled to very low temperatures before becoming liquid, leading liquid nitrogen to be a very effective cryogenic liquid.
The act of breaking apart the two atoms in a nitrogen molecule is called “nitrogen fixation“. Plants get the nitrogen that they need from the soil, where it has already been fixed by bacteria and archaea. Bacteria and archaea in the soil and in the roots of some plants have the ability to convert molecular nitrogen from the air (N2) to ammonia (NH3), thereby breaking the tough triple bond of molecular nitrogen. Such organisms are called “diazotrophs“. From here, various microorganisms convert ammonia to other nitrogen compounds that are easier for plants to use.
Lightning and high-energy solar radiation can also split the nitrogen molecule, and therefore also fixes the nitrogen in the air. However, the amount of nitrogen fixed by lightning and solar radiation is insignificant compared to the amount fixed by diazotrophs in the soil and in the roots.

Que 12. Water-based liquids can be described as acidic, neutral, or basic, with respect to pH. Which of these describes milk?
Ans 12. Milk is close to a neutral pH, but it’s slightly acidic thanks in part to the lactic acid it contains.

Que 13. Most of our coins are made from which metal?
Ans 13: Copper.

Que 14. At room temperature, what is the only metal that is in liquid form?
Ans 14. Mercury

Que 15. Which gas, discovered in 1898, is used in car headlamps to produce adequate light immediately upon switching on?
Ans 15. Xenon

Que 16. What is it about the ocean that makes it look blue when it reflects the sky?
Ans 16. Water absorbs red light due to vibrational transitions of the molecules, leaving the blue light to reflect back. For the same reason, large volumes of snow and ice also have a blue tinge.

Que 17. Who is credited with the invention of the modern periodic table?
Ans 17. Mendeleev (sometimes spelled Mendeleev) is credited with creating the modern periodic table, although his table was based on increasing atomic mass rather than atomic number. Mendeleev’s table grouped elements according to common properties and periodic trends.

Que 18. What kinds of compounds cannot be mixed with water?
Ans 18. Organic solvents.

Que 19. What is the third most common gas found in the air we breathe?
Ans 19. Argon (around 1%)

Que 20. What is nitrous oxide more commonly known as?
Ans 20. Laughing gas (N2O).

Que 21. What makes a “fluorescent” highlighter marker so bright?
Ans 21. Fluorescent highlighter markers are so bright because they are literally fluorescent. When used to describe highlighters, the word “fluorescent” is not a vague term that means “extra bright”. Rather, this word is an exact, scientific term indicating that the highlighter ink exhibits fluorescence. Fluorescence is the phenomenon where a material absorbs light of a certain color and then emits light of a different color with a longer wavelength. The most striking type of fluorescence involves the absorption of ultraviolet rays (which humans can’t see) and the subsequent emission of light in the visible spectrum (which humans can see). Because humans can’t see the original ultraviolet light, a fluorescent object looks like it is glowing mysteriously on its own when it is illuminated only by ultraviolet rays in a dark room

Que 22. We can’t live without iron. Where in the body are most of the iron located?
Ans 22. Most of the body’s iron is locked up in the hemoglobin found in red blood cells, used for oxygen transport.

Que 23. Which type of chemical reacts with acids to give water and salt?
Ans 23. Bases.

Que 24. Why is ice slippery?
Ans 24. On its own, ice is not slippery. When you step onto an icy sidewalk, you do indeed feel a slippery surface. But the slipperiness is caused by a thin layer of liquid water and not directly by the solid ice itself. Water on a smooth surface is slippery because water is a low-viscosity liquid. As such, there are no permanent intermolecular bonds in liquid water, and the transient intermolecular bonds are weak. This means that water molecules can move about freely, slide past each other easily, and fill any microscopic holes or cracks that would snag an object.

Que 25. Brass is a metal alloy made up of which two elements?
Ans 25. Copper (66%) and zinc (34%)

Chemistry Questions with Surprising Answers

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