Topic 2: Introduction to Chemistry

Question 1

What is matter?

Answer 1

Anything that occupies space and has mass.

Question 2

How many naturally occuring elements are there?

Answer 2

There are 92 naturally occuring elements.

Question 3

What are the primary elements that the human body is composed of?

Answer 3

Oxygen (O)

Carbon (C)

Hydrogen (H)

Nitrogen (N)

96.3% Total

Question 4

What the the common trace elements found in the human body?

Answer 4

Calcium (Ca)

Phosphorus (P)

Potassium (K)

Sulfur (S)

Sodium (Na)

Chlorine (Cl)

Magenesium (Mg)

3.7% Total

Question 5

What do trace elements do?

Answer 5

• Some trace elements are required to prevent diseases.
• Iron allows your blood to transport oxygen.
• Iodine contributes to thyroid hormones.
• Fluoride helps prevent tooth decay.

Question 6

What are isotopes?

Answer 6

Isotopes are elements that have different numbers of neutrons/atomic masses.

¹²₆C = 12 amu, 6 protons, 6 neutrons

¹³₆C = 13 amu, 6 protons, 7 neutrons

¹⁴₆C = 14 amu, 6 protons, 8 neutrons

Question 7

How can radioactive isotopes harm us?

Answer 7

Living cells cannon distinguish between isotopes of the same element.

Question 8

How can radioactive isotopes help us?

Answer 8

Radioactive compounds in metabolic processes can act as traces that are detectable and able to be monitored.

Positron-Emission Tomography (PET) scans can detect the location of radioactive isotopes.

PET scans can be used to diagnose heart disorders and cancer as well as being used in brain research.

Question 9

What is a covalent bond?

Answer 9

When two atoms (each who have one unpaired electron) share a pair of electrons.

Question 10

What is electronegativity?

Answer 10

The attraction or pull for shared electrons.

The higher the electronegativity, the stronger the pull.

Question 11

What is an ionic bond?

Answer 11

The transfering of one or more electron(s) from an anion (Negatively charged Ion) to a cation (Positively charged Ion).

Cl^- + Na⁺ = NaCl

Question 12

What is cohesion?

Answer 12

The tendency of molecules of the same kind to stick together.

Question 13

What is adhesion?

Answer 13

The tendency of two different kinds of molecules to stick together.

Question 14

What is surface tension?

Answer 14

It is a property of cohesion amongst hydrogen bonds that allows for there to be a certain force required to break the surface of the water.

Question 15

What is thermal energy?

Answer 15

The energy associated with the random movement of atoms and molecules.

Question 16

What is heat?

…how is it measured?

Answer 16

The transfer of thermal energy from a warmer to a cooler body of matter.

Temperature measures the intensity of heat through the average speed of molecules in the body of matter.

Specific heat is the amount of thermal energy to raose the temperature of 1 gram of the substance by 1°C.

Question 17

How do hydrogen bonds function?

Answer 17

The absobtion of heat breaks hydrogen bonds.

The release of heat forms hydrogen bonds.

Question 18

What is a solution?

Answer 18

A homogeneous mixture one solvent (disolving agent) and one or more solutes (substance being disolved).

An aqueous solution is when water is the solvent.

Question 19

Why is water a good solvent?

Answer 19

Water contains polor covalent bonds.

Question 20

What is an acid?

Answer 20

A substance that donates hydrogen ions to solutions when disolved in water.

Question 21

What is a base?

Answer 21

A substance that reduces the hydrogen concentration of a solution.

Question 22

What is the pH scale?

Answer 22

A scale to describe how acidic or basic a solution is.

Question 23

What is ocean acidification?

Answer 23

Hydrogen Ions (H⁺) combine with carbonate ions (CO₃^2-) to form bicarbonate (HCO₃^-).

This reaction reduces the carbonate ion concentration lowers the rate of calcification for corals and other shell-building animals.