Week 0 basics revision

Question 1

What is a superoxide anion?

Answer 1

An oxygen molecule with an additional electron: O₂ + e^- → O₂^-

Question 2

How do you write the Na cation equation?

Answer 2

Na → Na⁺ + e^-

Question 3

What is the definition of a compound?

Answer 3

Two or more elements in a definite and unchanging proportion - a substance containing two or more elements.

Question 4

What is the name of a positively charge ion?

Answer 4

A cation.

Question 5

What is the name of a negatively charge ion?

Answer 5

An anion.

Question 6

What is an ionic compound?

Answer 6

An array of ions, not individial molecules. E.g. NaCl consists of Na⁺ and Cl^- ions.

Question 7

What are two major laws of chemistry?

Answer 7

The law of conservation of mass and the law of definite proportion. I.e. In a given chemical compound, the elements are always combine in the same proportions by mass, and chemical reaction cannot cause the loss or gain of mass.

Question 8

What is the law of multiple proportions?

Answer 8

Whenever two elements can form more than one compound, the different masses of one element that combines with the same mass of the other element are in the ratio of small whole numbers.

Eg: sulpher dioxide SO₂: 1 x S, 2 x O, ratio 1:2

Sulpher trioxide SO₃: 1 x S, 3 x O, ration 1:3

Question 9

What is the mass of an electron?

Answer 9

9.09x10^-31kg or 5.4858x10^-4u

Question 10

What determines the species of an atom?

Answer 10

The number of protons it has.

Question 11

What is the mass of a neutron

Answer 11

1.6749 x 10^-27kg or 1.0087u

Question 12

What is the mass of a proton?

Answer 12

1.6726 x 10^-27kg or 1.0073u

Question 13

What is the charge of an electron?

Answer 13

-1.6022 x 10^-19 C

Question 14

What is the charge of a proton?

Answer 14

+1.6022 x 10^-19 C

Question 15

What is the symbol for an atom’s mass number? What does ‘mass number’ mean?

Answer 15

A. The number of protons and neutrons in the nucleus. This indicates what isotope it is.
An atom’s given atomic mass number is the average of masses of naturally occurring isotopes.

Question 16

What is the symbol for an atom’s atomic number? What does ‘atomic number’ mean?

Answer 16

Z. How many protons (only) the nucleus contains. This indicates what species (element) the atom is.

Question 17

What is an isotope?

Answer 17

Atoms of an element with a different number of neutrons. E.g.

Question 18

What particles are neutrons and protons, but not electrons, made up of?

Answer 18

Quarks.

Question 19

What does it mean if an atom is radioactive?

Answer 19

The nucleus is unstable and undergoes spontaneous decay.

Question 20

What is a nuclide?

Answer 20

A nuclide (or nucleide, from nucleus, also known as nuclear species) is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons, Z, its number of neutrons, N, and its nuclear energy state.

Question 21

What is the term for an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons, Z, its number of neutrons, N, and its nuclear energy state.

Answer 21

Nuclide.

Question 22

What is a radionuclide?

Answer 22

A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable.

Question 23

What does the symbol u stand for?

Answer 23

The dalton or unified atomic mass unit (symbols: Da or u) is defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted m_u, is defined identically, giving m_u = m(¹²C)/12 = 1 Da

It is equal to 1.66054 x 10^-27kg

or 1/12th the mass of 1 atom of ¹²C

Question 26

What is the SI (International System of Units) unit for temperature?

Answer 26

Kelvin. Symbol: K

0K = -273.15ºC

0ºC = 273.15K

1 Kelvin = 1ºC

Question 27

What is the value of a mole?

Answer 27

6.022×10²³

Question 28

What is the symbol and value of Avogadro’s constant?

Answer 28

Symbol: N_A

N_A = 6.022x10²³ mol^-1