Chapter 3: Basic Review.

Question 1

Scientific models are like architects’ models; they are ___________ representations of something rea.

Answer 1

simplified but useful

Question 2

According to the model presented in this chapter all matter is composed of tiny _________.

Answer 2

Particles

Question 3

According to the model presented in this chapter, the amount of motion of particles is proportional to __________.

Answer 3

Motion

Question 4

Solids, gases, and liquids differ in the freedom of motion in their particles and in how strongly the particles _______ each other.

Answer 4

attract

Question 5

An increase in temperature usually causes a solid to ________ somewhat.

Answer 5

vaporize

Question 6

Particles in a liquid are still close together, but there is generally more ______ between them than in a solid. Thus, when a solid substance melts to form a liquid, it usually _____ to fill a slightly larger volume.

Answer 6

empty space + expands

Question 7

The freedom of movement of particles in a liquid allows liquids to _________, taking on the shape of their container.

Answer 7

flow

Question 8

When a liquid’s temperature is higher, its particles are moving faster and are therefore more likely to ________ from the liquid

Answer 8

escape

Question 9

The average distance between particles in a gas is about __________ the diameter of each particle. This leads gas particles to take up only about __________ of the total volume. The other __________ of the total volume is empty space.

Answer 9

0.1%, 99.9%, 70%

Question 10

According to our model, each particle in a gas moves freely in a __________ until it collides with another gas particle or with the particles of a liquid or solid.

Answer 10

straight line path

Question 11

A liquid has a constant volume, but the__________ movement of the gas particles allows gasses to expand to fill a container of any shape or volume.

Answer 11

busy

Question 12

Elements are substances that cannot be chemically converted into _________ ones.

Answer 12

simpler

Question 13

By the year 2014, ______ elements had been discovered, but ______ of these elements are not found naturally on earth, and chemists don’t generally work with them.

Answer 13

118; 28

Question 14

The periodic table is arranged in such a way that elements in the same _______ have similar characteristics.

Answer 14

vertical column

Question 15

Metals are malleable, which means they are capable of being ______ by blows of a hammer.

Answer 15

extended/shaped

Question 16

At room temperature and normal pressures, most of the elements are ________, two of them are _____, and eleven are ______.

Answer 16

solid, liquid, and gas.

Question 17

For our purposes, we can think of the atom as a sphere with a diameter of about __________ meter.

Answer 17

10^-10

Question 18

A 1/2-carat diamond contains about 5 x 10^21 atoms of carbon. If these atoms were arranged in a straight line with each one touching its neighbors, the line would stretch from here to the ______.

Answer 18

sun

Question 19

We know that objects of opposite charge attract each other and that objects of the same charge _____ each other.

Answer 19

repels

Question 20

The diameter of a typical nucleus is about _______ meter.

Answer 20

10^-15

Question 21

Nearly all the mass of the atom and al of its positive charge are found in a nucleus about _______ the diameter of the atom itself.

Answer 21

10^-10

Question 22

Chemists use a model for electrons in which each electron is visualized as generating a ______- of negative charge that surrounds the nucleus.

Answer 22

cloud

Question 23

When an atom _______ one or more electrons, it then has more electrons than protons and more minus charge than plus charge. Thus it becomes an anion, which is negatively charged.

Answer 23

loses

Question 24

Although all of the atoms of a specific element have the same number of ________________, they do not necessarily all have the same number of ____________.

Answer 24

protons, neutrons

Question 25

Atoms are assigned to elements on the basis of their _________ characteristics

Answer 25

chemical

Question 26

When an atom _______ one or more electrons, it then has more protons than electrons and more plus charge than minus charge. Thus it becomes a cation, which is positively charged.

Answer 26

gains

Question 27

Because it displays the ________________, the periodic table can be used to determine the number of protons and electrons in an uncharged atom of any element.

Answer 27

atomic number

Question 28

Each noble gas particle consists of a _______.

Answer 28

single atom

Question 29

Hydrogen gas is very similar to helium gas, except that each of the particles is a hydrogen ________.

Answer 29

atom

Question 30

Because of the size and number of carbon atoms in any normal sample of carbon, it is ______________ to count the atoms directly

Answer 30

impossible

Question 31

The unit most often used to describe the mass of atoms is the atomic mass unit, whose symbol is u or amu. An atomic mass unit is defined exactly ____________ the mass of an atom of carbon-12.

Answer 31

half

Question 32

The atomic mass of any element is the _______ average of the masses of the ________ occurring isotopes of the element.

Answer 32

weighed ; naturally

Question 33

A mole is an amount of substance that contains the same number of particles there are in 12 g of carbon-12.

Answer 33

6.022 x 10^23

Question 34

The number of grams in the molar mass of an element is the same as the element’s

Answer 34

atomic mass