1.1The introduction to the particulate nature of matter

Question 1

Atom

Answer 1

Smallest unit of an elemetn

Question 2

Matter

Answer 2

anything with mass and volume (density)

Question 3

Pure substance

Answer 3

Uniform chemical composition and chemically bonded together. Include elements and compounds

Question 4

element

Answer 4

One kind of atom chemically bonded in a fixed ratio that cannot be broken down

Answer 5

i. subatomic particles
ii. isotopes
iii. atoms can gain or lose electrons
iv. atoms can split

Question 6

Compound

Answer 6

pure substance that has two or more kinds of elements chemically bonded together in fixed ratios. The properties of a compound are not those of its constituent elements.
(covalent bonds and ionic bonds)

Question 7

Mixtures

Answer 7

Two or more pure substances with no fixed ratio and no intermolecular force. They have their own individual properties. They include homogenous and heterogenous

1. the components can be elements or compounds
2. the compoenents retain their individual properties

Question 8

Homogenous (solutions)

Answer 8

mixture which has uniform compositions throughout the mixture and consists of only one phase (alloy, salt,air)

eg: alloys: bronze and steel

Question 9

Heterogeneous

Answer 9

mixture which has non-uniform properties and consists of separate phases. They can be seperated by mechanical means

Question 10

Solid

Answer 10

fixed volume and shape. Strong intermolecular force but not compressible. They are low in energy and vibrate in place.

Question 11

Liquid

Answer 11

fixed volume but no fixed shape but takes the shape of the container. Low intermolecular force and not compressible. They are higher in energy by breaking, reforming bonds and sliding. They are fluids that can diffuse.

Question 12

Gas

Question 13

Temperature

Answer 13

measure of the average kinetic energy of the particles of a substance.

Question 14

Diffusion

Answer 14

Liquids and gases are fluids which substances become evenly distributed due to random movement of particles

Question 15

states of matter

Answer 15

the kinetic energy of the particle is determined by temperature and pressure. kinetic energy is determined by temperature.

Question 16

Kinetic energy formula

Answer 16

As the K.E. of two substances at the same temperature is equal, this means there is an inverse relationship between mass and velocity. Substances with lower mass diffuse more quickly than those with greater mass, when measured at the same temperature

Question 17

Compare evaporation and boiling

Answer 17

Evaporation is the process of conversion of a liquid into vapours at any temperature below its boiling point at constant pressure. bubbles cannot form since the vapoour pressure is less than atmospheric pressure. Evaporation occurs regardless of the temperature because the air molecules that hit the surface provide the molecules some energy. Since a molecule’s kinetic energy is proportional to temperature, greater temperatures cause more evaporation.

• evaporation increases if there is increase temperature of the liquid and increases surface area

Boiling happens at a specific temperature and depends on the external pressure of the air. Bubbles can form and rise since the vapor pressure can overcome atmospheric pressure. In the process of boiling, temperature remains constant.

Question 18

Relationship between pressure, heat, vapor pressure and atmospheric pressure.

Answer 18

Atmospheric pressure keeps water and vapor in place. More liquid heated makes more vapor particles by increasing kinetic energy thus making more vapor pressure. Water vapor is constantly turned back and forth into water until “equilibrium” (condensing and boiling repeatedly at the same time) The boiling point is achieved through vapor pressure overcoming atmospheric pressure.

Question 19

vapour pressure

Answer 19

vapor pressure depends on the quantity of vapor particles. They are the particles heating the wall. It is dependent on the temperature by measuring the vapor in an equilibrium.

Question 20

pressure and boiling point graph

Answer 20

high boiling point ➤ higher vapour pressure meeting higher atmospheric pressure

low boiling point ➤ lower vapour pressure meeting lower atmospheric pressure.

Question 21

Explain what is happening to the particles in phases
a~b, b~c, c~d, d~e, e~f

Answer 21

a~b, c~d, e~f: solid is heated increasing the vibrational energy and frequency as the kinetic energy is increaased. This increases the temperature.

b~c: This is the melting point (0 Celsius water+ice). The temperature stays the same. Vibrations are sufficiently energetic to move the particles away from the fixed position. Less energy is added to break some intermolecular force.

d~e: this is the boiling point (100 Celsius water+steam). The temperature stays the same. More energy is added than melting to break all intermolecular bonds. Temperature does not increase as kinetic energy does not increase. Bubbles are visible throughout the volume of liquid.

Question 22

Different masses of iron have the same temperature. Compare the average kinetic energy and the total energy of the atoms in the objects.

Answer 22

• avergae kinenetic energy of atoms will be the same.
• the total energy ofthe atoms will be greater in an object of larger mass