Chapter 2

Question 1

Elements

Answer 1

Substances that can’t be broken down into simpler substances by ordinary chemical reactions

Question 2

Four primary elements

Answer 2

Oxygen, carbon, hydrogen, nitrogen(азот)

Question 3

Atom

Answer 3

The smallest unit of an element which is made up of neutrons, protons and electrons.

Question 4

Identified by the number of protons

Answer 4

Atom

Question 5

Atomic mass

Answer 5

Protons + neutrons

Question 6

Molecule

Answer 6

A group of atoms held together by covalent bonds and have no overall charge

Question 7

Ionic bond

Answer 7

A bond between atoms that is formed by losing and gaining an electron.

Opposite charges-they are attracted. Atom looses electron-now charge is positive. Atom gains electron - charge becomes negative.

Stronger than covalent bond.

Question 8

Chemical reactions

Answer 8

📌Reactant+reactant=product

📌Reactants undergo chemical reactions

📌Products are formed in chemical reactions

Question 9

Metabolism

Answer 9

All the chemical reactions that occur in the human body.

Question 10

Solution

Answer 10

A mixture in which one or more substances are evenly distributed in another substance.

• salt water
• look aid

Question 11

Mixture

Answer 11

A combination of substances in which the individual components retain their chemical properties.

• sand and salt
• sand and water

Question 12

pH

Answer 12

pH is a measure of how acidic or basic substance is.

• scale 0-14
• below 7 - acidic
• above 7 - basic