Chemistry Compounds and Elements

Questions and Answers

What is the primary difference between elements and compounds?

Elements can be broken down into simpler substances, while compounds cannot.

Elements are only found in nature, while compounds are synthetic.

Elements are made up of one type of atom, while compounds are made up of multiple different atoms. (correct)

Elements consist of multiple different atoms, while compounds consist of only one atom.

The atomic number of an atom is determined by the number of neutrons it contains.

False

What do we call atoms that have the same number of protons but different numbers of neutrons?

Isotopes

The mass number of an atom is the sum of and in its nucleus.

protons, neutrons Signup and view all the answers

Match the following subatomic particles with their characteristics:

Protons = Positively charged and found in the nucleus Neutrons = Neutral charge and found in the nucleus Electrons = Negatively charged and orbit around the nucleus Atomic number = Number of protons in an atom Signup and view all the answers

Which of the following statements about ionic bonds is true?

In ionic bonds, one atom gives up electrons and becomes positively charged. Signup and view all the answers

The pH scale measures the concentration of hydrogen ions in a solution.

True Signup and view all the answers

What does the conservation of mass principle state?

The mass we start with will be the same as the mass at the end. Signup and view all the answers

What pH range indicates a strong acid?

0-7 Signup and view all the answers

All bases feel slippery and have a sour taste.

False Signup and view all the answers

What ion does an acid release in an aqueous solution?

H+ Signup and view all the answers

A substance that turns red litmus paper blue is classified as a __________.

base Signup and view all the answers

Match the following substances with their examples:

Hydrochloric Acid = Stomach acid Sodium Bicarbonate = Baking soda Sulfuric Acid = Car batteries Aluminium Hydroxide = Antacids Signup and view all the answers

Which of the following acids is commonly used in fertilizers?

Nitric acid Signup and view all the answers

Study Notes

Compounds vs. Elements

Atoms can form molecules or crystal lattices.
An element consists of only one type of atom or molecule.
A compound contains multiple types of atoms or molecules.

Parts of an Atom

Atoms consist of three subatomic particles: protons, neutrons, and electrons.
Protons and neutrons are clustered in the nucleus, while electrons move rapidly in an electron cloud surrounding the nucleus.

Atomic and Mass Numbers

The atomic number is determined by the number of protons in an atom's nucleus, defining the element.
The mass number is the total of protons and neutrons in the nucleus.
Electrons in a neutral atom equal the number of protons.

Isotopes

Isotopes are atoms with the same number of protons but different numbers of neutrons.

Ionic Bonds

Ionic bonds form when one atom donates electrons to another.
The donating atom becomes positively charged, while the receiving atom becomes negatively charged.

Types of Chemical Equations

Written equations express chemical reactions using words.
Symbol equations express reactions using chemical symbols.

Conservation of Mass

Mass is conserved in chemical reactions; initial mass equals final mass.

pH Scale

The pH scale measures acidity or basicity, calculated as pH = -log[H+].
Acids have a pH of 0-7 (stronger with lower values).
Bases have a pH of 7-14 (stronger with higher values).
Acids produce hydrogen ions [H+] in aqueous solutions.
Bases produce hydroxide ions [OH-] in aqueous solutions.

Characteristics of Acids

Sour taste and corrosive nature.
Turns blue litmus paper red.
Reacts with metals to produce hydrogen gas.
Conducts electricity.
Strong acids have a high concentration of hydrogen ions, while weak acids have a lower concentration.

Characteristics of Bases

Bitter taste and slippery feel.
Turns red litmus paper blue.
Caustic and can burn living tissue.
Strong bases have a high hydroxide ion concentration; weak bases have a lower concentration.

Examples of Acids

Carbonic acid (H2CO3): found in soft drinks and seltzer water.
Hydrochloric acid (HCl): present in stomach acid.
Nitric acid (HNO3): used in fertilizers and explosives.
Sulfuric acid (H2SO4): common in car batteries.

Examples of Bases

Aluminium hydroxide (Al(OH)2): used in antacids and deodorants.
Calcium hydroxide (Ca(OH)2): found in plaster and lime.
Sodium bicarbonate (NaHCO3): known as baking soda.
Sodium hydroxide (NaOH): found in cleaners and lye.

Acid Reactions

Acids can corrode metals, forming salts and hydrogen gas.
In this context, "salt" refers to any compound formed from the reaction of an acid with a base, not just sodium chloride (NaCl).

Description

This quiz focuses on the basic concepts of compounds and elements in chemistry. It covers the nature of atoms, molecules, and the formation of crystal lattices. Additionally, it touches on the components of an atom, including protons, neutrons, and electrons.