Chapter 4- The chemistry of life (1)

Question 1

How is matter moved around?

Answer 1

By energy

Question 2

Matter can exist in three states:

Answer 2

Solids, liquids, and gases

Question 3

What are the properties of a solid, liquid and gas?

Answer 3

Solid has a definite shape and volume- examples are bones, teeth

Liquid has a definite volume, but they can flow and fill any space- examples include blood plasma

Gases have no defined shape or volume- example is air

Question 4

What is energy?

Answer 4

The ability to put matter into motion

Question 5

Energy comes in two main types:

Answer 5

1- Kinetic energy- is that which moves things

2- Potential energy- is stored energy. It is inactive energy that has potential to do work. When the energy is released, it becomes kinetic energy

Question 6

What are other main types of energy

Answer 6

1- Chemical energy- stored in chemical bonds. Chemical reactions rearrange atoms.

2- Electrical energy- movement of charged particles (ions). The ions move along cell membranes.

3- Mechanical energy- Energy directly involved in moving matter

4- Radiant energy (electromagnetic radiation) - energy that travels in waves

Question 7

ENERGY CAN NEITHER

Answer 7

BE CREATED OR DESTROYED

Question 8

4 elements make up most of our body weight. What are they?

Answer 8

1- Carbon
2- Oxygen
3- Hydrogen
4- Nitrogen

Question 9

Every element is made from an…

Answer 9

Atom

Question 10

What does the structure of an atom contain?

Answer 10

Protons
Neutrons
Electrons

Question 11

The protons and neutrons make up what part of the atom?

Answer 11

The nucleus

Question 12

What charge does the nucleus have?

Answer 12

A positive charge

Question 13

Why are atoms electrically neutral?

Answer 13

Because an atom will have the same number of protons and electrons

Question 14

What is an isotope?

Answer 14

Forms of the same element that have the same number of protons and electrons but a different number of neutrons.

Question 15

What are radioisotopes?

Answer 15

Isotopes that have more neutrons in the nucleus than protons and electrons. This is seen as unstable.

Question 16

Why are radioisotopes dangerous?

Answer 16

Because they are radioactive which means they can spontaneously decompose to form unstable atoms.

Question 17

How do radioisotopes spontaneously decompose?

Answer 17

Through atomic decay

Question 18

What are the types of energy that are released during atomic decay?

Answer 18

1- Alpha particles
2- Beta particles
3- Gamma rays

Question 19

Molecules can be of two types. What are they?

Answer 19

1- Molecules of an element- when atoms of the same element combine, e.g, H2

2- Molecules of a compound- when different kinds of atom combine, e.g, H2O

Question 20

What is a mixture?

Answer 20

A mixture is when two or more components are physically intermixed.

Question 21

What are the 3 types of mixtures?

Answer 21

1- Solutions- where solute particles are very tiny, e.g., water

2- Colloids- this is where solute particles are larger than in a solution, e.g., jelly

3- Suspensions- this is where solute particles are very large, e.g., blood

Question 22

Is there chemical bonding between components of a mixture?

Answer 22

No

Question 23

How can mixtures be separated physically?

Answer 23

1- Straining
2- Evaporating
3- Filtering

Question 24

Compounds need what type of bonds to be broken in order to separate?

Answer 24

Chemical bonds

Question 25

Are mixtures heterogenous or homogenous?

Answer 25

Both