15 Chemistry Interview Questions and Answers

Chemistry is the study of matter and the changes it undergoes. It is a branch of science that has been around for centuries, and it is one of the most important subjects you can study if you want to pursue a career in the sciences.

If you are interested in a career in chemistry, you will need to be able to answer some tough questions during your interview. This article will give you some sample questions and answers to help you prepare for your chemistry interview.

1. What is the difference between an atom and a molecule?

This question tests your knowledge of the basic elements that make up matter. Your answer should show you understand the difference between these two concepts and how they relate to each other. You can define both terms, explain their differences and give an example of when you used this skill in a previous role.

Example: “Atoms are the smallest particles of matter that exist. They consist of protons, neutrons and electrons. Molecules are formed by atoms that bond together. There are many different types of molecules, such as water, carbon dioxide and salt. In my last position, I had to separate sodium chloride from water so we could use it for cleaning.”

2. How do you calculate Molarity?

This question is a great way to test your chemistry skills. Molarity is the measure of concentration for a solution, and it’s important that you can calculate this accurately in any situation. To answer this question, explain how you would perform the calculation and provide an example of when you’ve done so in the past.

Example: “Molarity is calculated by dividing the number of moles per liter of solution. In my last role as a chemist, I had to determine the molarity of a solution to ensure it was safe for use. I used a calculator to divide the number of moles of sodium hydroxide with the volume of water in the container. The result was 0.5 molar.”

3. What is the Periodic Table of Elements?

The Periodic Table of Elements is a chart that shows the different elements and their properties. It’s an important tool for chemists, so your interviewer may ask you this question to see if you have basic knowledge about chemistry. To answer this question, define what the Periodic Table of Elements is and give examples of its uses.

Example: “The Periodic Table of Elements is a chart that shows all 118 known elements and their properties. I used it in my last job as a chemist to determine which elements were present in samples we tested. The table also helps me understand how elements interact with each other.”

4. Can you explain what density means in the context of chemistry?

This question is a great way to test your knowledge of chemistry and how it applies to the workplace. When answering, try to use examples from your previous experience that show you understand what density means in relation to chemistry.

Example: “Density refers to the mass per unit volume of a substance. It’s important to know because it can help us determine whether two substances are similar or different. For example, if I’m working with chemicals that have different densities, I’ll need to take this into account when mixing them together. If they have the same density, then there won’t be any issues.”

5. What is covalent bonding?

This question tests your knowledge of a specific chemical process. It also allows you to show the interviewer that you can break down complex processes into simple terms and concepts. In your answer, define covalent bonding using basic language and explain how it relates to chemistry in general.

Example: “Covalent bonding is when two atoms share electrons with each other. This type of bond is very strong because the electrons are shared between both atoms. Covalent bonds are important for organic molecules like proteins and DNA. They’re also essential for life as we know it.”

6. What are some examples of chemical reactions?

This question is a basic test of your knowledge about chemistry. It’s important to show the interviewer that you understand the basics of this field and can apply them in real-world situations.

Example: “Chemical reactions are when two or more substances combine, separate or change into different compounds. Some examples include combustion, rusting, oxidation and electrolysis. Chemical reactions occur all around us every day. For example, when we put salt on ice, it melts because of a chemical reaction between the salt and water.”

7. How do molecules behave differently when subjected to different temperatures?

This question is a great way to test your knowledge of chemical reactions and how they change when exposed to different temperatures. When answering this question, it can be helpful to provide an example of how molecules behave differently at various temperatures.

Example: “Molecules have varying degrees of energy depending on their temperature. At higher temperatures, the molecules are more energetic and move faster than at lower temperatures. This means that at high temperatures, molecules will collide with each other more often and form bonds more quickly. However, at low temperatures, the molecules are less energetic and don’t collide as much. As a result, it takes longer for them to bond together.”

8. What does it mean for something to be ‘pure’?

This question can help the interviewer assess your knowledge of chemical purity. Use examples from your experience to show that you know what it means for something to be pure and how this concept applies in a lab setting.

Example: “Pure simply means that there is no other substance present. For example, when I was working with my previous employer, we were tasked with creating a solution that was 100% sodium hydroxide. This meant that there was no water or any other substances present in the solution. In order to achieve this level of purity, we had to use a process called distillation where we boiled off all of the water until only sodium hydroxide remained.”

9. If two chemicals have the same molar mass, then how can you differentiate them from each other?

This question is a great way to test your knowledge of chemical formulas and how they work. You can answer this question by explaining the process for identifying two chemicals that have the same molar mass.

Example: “The easiest way to differentiate between two chemicals with the same molar mass is through their formula. For example, if you had two chemicals with the same molar mass but different molecular masses, then you would know that they are different because each molecule has its own unique formula. The formula is what determines the number of atoms in a compound, so it’s important to be able to identify them.”

10. What is chromatography? What are its uses?

This question tests your knowledge of a specific chemical process. It also allows you to show the interviewer that you can apply what you know about chromatography to real-world situations.

Example: “Chromatography is a technique used for separating and analyzing compounds in mixtures. The method uses a stationary phase, which is usually a solid material like paper or silica gel, and a mobile phase, which is usually a liquid solvent. Chromatography is useful for identifying unknown substances, detecting impurities in drugs and food products and determining the purity of chemicals.”

11. Why is Chromatography useful in forensic science?

This question is a great way to show your knowledge of chemistry and how it can be applied in different industries. When answering this question, you should explain the process of chromatography and why it’s used in forensic science. You can also mention that it helps identify fingerprints and other evidence at crime scenes.

Example: “Chromatography is an important tool for forensic scientists because it allows them to separate compounds based on their solubility. This means they can use it to analyze samples from a crime scene and determine what substances are present. For example, if someone was poisoned, a forensic scientist could use chromatography to find out which substance caused the poisoning.”

12. What is Density-Independent Filtration?

This question tests your knowledge of a specific chemical process. Your answer should show that you understand the purpose and function of Density-Independent Filtration, but also how it relates to other processes in the industry.

Example: “Density-Independent Filtration is a method used for separating particles from liquids by using gravity instead of pressure. It’s often used when filtering solutions with high salt concentrations because it doesn’t require additional energy to operate. In my last role as a chemist, I used this method to separate sodium chloride from water samples so I could test their pH levels.”

13. What is the difference between electron configuration and orbital notation?

This question tests your knowledge of the two most common ways chemists describe chemical structures. Your answer should show that you understand how to use both methods and when each is appropriate.

Example: “Electron configuration describes a molecule’s structure by listing its valence electrons, or those in outermost energy levels. Orbital notation lists all the orbitals involved in bonding between atoms and shows which atom has what electron. It also indicates the number of electrons in each orbital.”

14. What are the main differences between ionic and covalent bonds?

This question tests your knowledge of the two main types of chemical bonds. It also shows how you apply that knowledge to solve problems and make decisions. Your answer should show that you understand the differences between ionic and covalent bonds, as well as when each is appropriate.

Example: “Ionic and covalent bonds are both important in chemistry because they’re what hold molecules together. Ionic bonds occur when one atom loses an electron to another atom. This creates a positively charged ion on one side and a negatively charged ion on the other. Covalent bonds occur when two atoms share electrons with each other. They create a shared pair of electrons between the two atoms.”

15. What is the purpose of using concentrated sulfuric acid?

This question tests your knowledge of the purpose and function of a specific chemical. When answering this question, it can be helpful to describe what concentrated sulfuric acid is and how you would use it in a laboratory setting.

Example: “Sulfuric acid is an extremely corrosive liquid that’s used for many different purposes in chemistry. It’s often used as a catalyst or reagent in reactions because of its ability to dissolve metals and other compounds. In my last role, I used concentrated sulfuric acid to dissolve metal samples so they could be analyzed by spectroscopy.”