Chemistry Exam#1

What branch of science is chemistry?

Chemistry is the branch of science that deals with the nature of matter and energy.

When we study chemistry, there are two ways to look at it. What is it?

Macroscopic and microscopic.

What are the scientific methods?

1. Observation and experiment, 2. Hypothesis, 3. Law, 4. Theory

When we study chemistry, we follow three principles. What are those principles?

Describe what change, what happened to cause this change, and why the sample has exhibited a specific change?

What is scientific notation?

Scientific notation is an easy way to write a very small or very large number.

Why do we put an element in the same column as to others?

They share similar chemical and physical characteristics because they have the same number of valence electrons.

When you look at an atom, identify protons, electrons, and neutrons.

Protons are carrying a charge unit of + 1, neutron carries no charge, electrons carries a charge unit of - 1.

What are the percentage of oxygen, carbon, hydrogen, nitrogen, and calcium in the human body?

Oxygen: 65%, Carbon: 18%, Hydrogen 10%, Nitrogen 3%

Who are the two scientist and philosophers?

Leucippus and Democritus.

Electrons were discovered by who?

Electrons were discovered by JJ Thompson.

By looking at the periodic table, there are two electrons that appears as liquid. What are they?

They are Mercury (Hg) and Bromine (Br).

How can you find something that has an isotope?

When they have the same number of protons but different number of neutrons.

What are the similarities/differences between C12 and C13?

The similarities are having the same atomic number, while the atomic mass is different. In this case atomic mass is 12 and 13 respectfully.