Question 1

Which statement best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A scientific law is a summary of observed phenomena, while a theory provides an explanation for those phenomena.

Question 2

Which of the following is an example of a physical change?

Accepted Answer

Dissolving sugar in water.

Question 3

Which scientist is credited with the discovery of the electron?

Accepted Answer

J.J. Thomson

Question 4

What is the correct SI unit for measuring mass?

Accepted Answer

kilogram ($$kg)$$

Question 5

A sample of water has a mass of $$250\ g$$ and a volume of $$250\ mL. $$What is its density?

Accepted Answer

$$1.0\ g/mL$$

Question 6

Which of the following best describes an ion?

Accepted Answer

An atom or molecule with a net electric charge due to the loss or gain of electrons.

Question 7

Which law states that mass is neither created nor destroyed in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Question 8

Convert $$5.0\ cm^3$ to mL$ using SI unit conversions.

Accepted Answer

$$5.0\ mL$$

Question 9

Which element is classified as a metalloid among the first 36 elements of the periodic table?

Accepted Answer

Silicon ($$Si)$$

Question 10

A neutral atom of chlorine has 17 protons. How many electrons does it have?

Accepted Answer

17

Question 11

Which scientist proposed the nuclear model of the atom after the gold foil experiment?

Accepted Answer

Ernest Rutherford

Question 12

What is the atomic number of oxygen?

Accepted Answer

8

Question 13

Which of the following is a chemical property?

Accepted Answer

Reactivity with acid

Question 14

Which SI prefix represents $$10^{-6}$$?

Accepted Answer

micro

Question 15

If an atom has 12 protons, 12 neutrons, and 10 electrons, what is its charge?

Accepted Answer

$$+2$$

Question 16

Which statement about the periodic table is correct?

Accepted Answer

Elements are arranged by increasing atomic number.

Question 17

Which of the following is NOT a subatomic particle?

Accepted Answer

Molecule

Question 18

A compound contains $$2$$ atoms of hydrogen and $$1$$ atom of oxygen. What is its chemical formula?

Accepted Answer

$$H_2O$$

Question 19

Which scientist is credited with organizing the first periodic table?

Accepted Answer

Dmitri Mendeleev

Question 20

A student measures the mass of a metal sample as $$15.0\ g$$ and its volume as $$3.0\ cm^3$. What is the density of the metal?

Accepted Answer

$$5.0\ g/cm^3$

Introduction to Chemistry: Foundational Concepts and Key Topics

Guida di studio - Domande di pratica