Chemistry First Semester Final Exam 24/25

Front

What does the atomic mass of an element represent?

Back

The atomic mass represents the mass of an atom, typically measured in atomic mass units (amu), which is approximately equal to the number of protons and neutrons in the atom's nucleus.

Front

What is condensation in terms of phase changes?

Back

Condensation is the process where a gas transforms into a liquid, typically when it cools down.

Front

How do you calculate density?

Back

Density is calculated by dividing mass by volume (Density = Mass/Volume).

Front

What is a physical property? Give an example.

Back

A physical property is a characteristic of a substance that can be observed without changing its chemical composition. Example: odor.

Front

Why should all chemicals in the lab be considered dangerous?

Back

All chemicals should be considered dangerous because they can pose health risks, react unpredictably, or cause harm if not handled properly.

Front

What is the significance of significant figures in calculations?

Back

Significant figures indicate the precision of a measurement and ensure that calculations reflect the accuracy of the data used.

Front

What is the difference between a chemical change and a physical change?

Back

A chemical change results in the formation of new substances, while a physical change alters the form or appearance of a substance without changing its chemical composition.

Front

Define the term 'element' in chemistry.

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means and is made up of atoms with the same number of protons.

Front

What is the atomic number of an element?

Back

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

Front

What is the process of evaporation?

Back

Evaporation is the process where liquid turns into gas at temperatures below its boiling point.