mod 2

Question 1

What is an isotope

Answer 1

. Have same number of electrons but different number of neutrons
. Have same chemical properties because same electrons in outer shell

Question 2

What is an ion

Answer 2

. A positively or negatively charged atom

Question 3

What is relative atomic mass

Answer 3

. Average mass of an atom relative to 1/12th The mass of one atom of carbon 12

Question 4

What is relative isotopic mass

Answer 4

. Mass of the isotope compare to 1/12 the mass of a carbon 12 atom

Question 5

What is weighted mean mass

Answer 5

. Mr taking into account the relative abundance of isotopes

Question 6

How do you calculate percentage by mass of an element

Answer 6

Percentage by mass = mass of element/mass of compound X 100

Question 7

What is molar gas volume

Answer 7

. Volume occupied by one mole of gas, molar gas volume is dependent on temperature and pressure

Question 8

What is a standard solution

Answer 8

. Always made using volumetric flask
. Is a solution of known concentration

Question 9

What factors can affect percentage yield

Answer 9

. Reaction may not go to completion
. Reactants may not be pure
. Other reactions me occur which leads to byproduct
. Products may be left behind in the reaction vessel
. Separation of purification of the products may result in loss of some of the products

Question 10

How do you calculate percentage yield

Answer 10

. Percentage yield = actual yield/theoretical yield × 100

Question 11

How do you calculate percentage Atom economy

Answer 11

. Percentage Atom economy = MR (desired products)/MR (all products) × 100

Question 12

What is a hydrated salt and an anhydrous salt

Answer 12

. Contains water of crystallisation
. Contains no water of crystallisation

Question 13

What is empirical formula

Answer 13

. Simplest whole number ratio of atoms present in a compound

Question 14

What is the molecular formula

Answer 14

. The actual number of atoms of each element in a molecule

Question 15

What is an acid

Answer 15

. Proton donor

Question 16

What is a strong acid

Answer 16

. Dissociate volume water into H plus ions Where is a weak acid or partially

Question 17

What is a base

Answer 17

. Proton acceptor

Question 18

What is an alkali

Answer 18

. Releases 0H minus ions in a solution

Question 19

What is a salt

Answer 19

. When the H plus in an acid is replaced by a metal ion or an ammonium ion

Question 20

How do you calculate percentage error

Answer 20

. Percentage error = total uncertainty/reading × 100

Question 21

What is a concordant titre

Answer 21

. Title values within 0.1 cm³ of each other

Question 22

What are oxidising and reducing agents

Answer 22

. A substance that is reduced in a redox reaction is known as an oxidising agent
. A substance that is oxidised in a redox reaction is known as a reducing agent

Question 23

How do you calculate the number of electrons in a shell

Answer 23

. Electrons = 2 (shell number squared)

Question 24

What is an orbital

Answer 24

. A region that can hold up to 2 electrons of opposite spins

Question 25

What shape is a P and S orbitals have

Answer 25

. P has Dumbo, S has spherical

Question 26

What is ionic bonding

Answer 26

. Strong electrostatic attraction between oppositely charged ions

Question 27

What is covalent bonding

Answer 27

. Shared pair of electrons

Question 28

What is the dative covalent bond

Answer 28

. Shared pair of electrons were both electrons come from the same atom

Question 29

What is metallic bonding

Answer 29

. Electrostatic attraction between positive metal ions and delocalised electrons

Question 30

What is the angle and bonding pair on low power number of each of these . Linear . Trigonal planar . Tetrahedral . Pyramidal . Octahedral . Non-linear

Answer 30

. 180° 2/4BP 0LP . 120° 3BP 0LP . 109. 5° 4BP 0LP . 107° 3BP 1LP . 90° 6BP 0LP . 104.5° 2BP 2LP

Question 31

How do you explain bond angles and shapes around an atom

Answer 31

. There are – bonding pairs – lone pairs around the – atom . There are – bonding regions/– regions of electron density . All electron pairs repel . Lone pairs of electrons repel more stronger than bonding pairs of electrons

Question 32

What is electronegativity

Answer 32

. Ability of an atom to attract the bonding electrons in a covalent bond . F is most electronegative atom on the periodic table

Question 33

Explain density of ice and water

Answer 33

. Ice is less dense than water . Hydrogen honds hold H2O molecules apart . Hydrogen bonds are relatively strong so ice has relatively high melting point

Question 34

What causes induced dipole dipole interactions

Answer 34

. Induced dipole dipole interactions caused by movement of electrons within the shells . Discord is instantaneous dipole across molecule . This induces a dipole in neighbouring molecule which in turn induced dipole in their neighbouring molecule . The small induced dipole is attract one another resulting in a weak intermolecular force

Question 35

What factors changed induced dipole dipole interaction strength

Answer 35

. Larger atoms contain more electrons will have stronger induced dipole dipole interactions . Molecules with larger surface areas will have stronger induced dipole dipole interactions

Question 36

How do you tell if a molecule is permanent or induced dipole dipole interactions

Answer 36

. If nonpolar will be induced . If contain hydrogen bonds is induced . It contains no hydrogen bonds is permanent

Question 37

What molecules of giant covalent lattice structures

Answer 37

. Diamond/silicone, graphite, Graphene

Question 38

Name the use of diamond, graphite, and Graphene

Answer 38

. Diamond used in diamond tip drills . Graphite used in pencils and As dry lubricant . Graphene used in high-speed electronics/aircraft