Basic chemistry

Question 1

what are the seven diatomic elements and what are their states at room temperature

Answer 1

(gas) oxygen
(gas) hydrogen
(gas) fluorine
(greenish gas) chlorine
(red liquid) bromine
(gas) nitrogen
(purple volotile solid) iodine (iodine can sublime directly into a gas)

Question 2

what are covalent bonds (1 point)

Answer 2

a sharing of electrons, since they have same electronegativeily , hydrogen + hydrogen is a non-polar covalent bond

Question 3

what are ionic bonds

Answer 3

they are assosicated with a tranfer of electrons, typically contain a metal and a non-metal

Question 4

ploar covalent bond

Answer 4

electrons are shared unequally
if electronegativity different is considered to be equal to or more than 0.5 its polar, if its less its usually non-polar

Question 5

what is a pure substance

Answer 5

has a constant composition, can be elements, compounds

Question 6

what is a mixture

Answer 6

a combination of multiple pure substances, and can have variable composition

Question 7

what is a homogenous mixture

Answer 7

mixture where the pure substances mix together (e.g. salt water), you don’t see the two disinguishable parts

Question 8

what is a heterogenous mixture

Answer 8

mixture where the pure substances don’t mix together (e.g. oil and water, sand and water)

Question 9

physical change vs chemical change

Answer 9

chemical identity changes in a chemical change,

Question 10

phyiscla propoerties

Answer 10

boiling point
melting point
ductility
malleability
colour
viscosity
density
mass, weight, volume

Question 11

chemical properties

Answer 11

flammability
corrosive
combustible
explosive
colour changing
pH

Question 12

law of conservation of mass

Answer 12

matter cannot be created or destroyed in a chemical reaction.

Question 13

law of definite proportions

Answer 13

the masses of each element in a given compound have constant composition.

Question 14

law of multiple proportions

Answer 14

the ratio of the masses of the 2nd element for different compounds can be reduced to whole numbers.

Question 15

when is an atom negative

Answer 15

more electrons and protons

Question 16

when is an atom positive

Answer 16

more protons than electrons

Question 17

what is an ion

Answer 17

a particle with an unequal number of protons and electrons

Question 18

what are cations

Answer 18

ions with positive charges, more protons than electrons, metals typically form cations

Question 19

what are anions

Answer 19

ions with negative charges, more electrons than protons non-metal typically form anions.

Question 20

what is a molecule

Answer 20

a molecule is a particle with multiple atoms

Question 21

how to find no. of electrons

Answer 21

is equal to atomic number minus the charge of the species.

Question 22

how to find no. of protons

Answer 22

is equal to atomic number of element

Question 23

how to find the no. of neutrons

Answer 23

difference between mass number an atomic number

Question 24

top number on elements

Answer 24

atomic number

Question 25

bottom number on element

Answer 25

atomic mass

Question 26

what is the atomic number of an element

Answer 26

atomic number of element is its identity, e.g. all isotopes of nitrogen will have 11 as atomic number, but atomic mass can change and will change for different isotopes

Question 27

how to calculate average atomic mass of element through isotopic percentages

Answer 27

mass of isotope 1st x percentage in decimal form + mass of 2nd isotope x percentage in decimal form .........

Question 28

what is an isotope

Answer 28

an isotope are composed of same element, different mass, both have same atomic number. Isotopes are substances that are composed of the same element but consist of different mass numbers and number of neutrons. They share the same atomic number and therefore the same number of protons.

Question 29

how to calculate percentage abundance of each isotopes

Answer 29

avefrage atomic mass = mass of isotope x percent abundance A = M x L e.g. 79.9 = 78.918 (x) + 80.916 (1 - x) 79.9 = 78.918x + 80.916 - 80.916x -1.016 = -1.998x x = 0.509

Question 30

what is an ion

Answer 30

An ion is a particle with unequal numbers of electrons and protons. Atoms have equal numbers of protons and electrons and are therefore electrically neutral.

Question 31

is an atom an ion, is an ion an atom???

Answer 31

i dont know dickhead

Question 32

ionic bond

Answer 32

Ionic bonds exist between metals and nonmetals and are made up of ions with positive and negative charges. occurs between ions. a transfer of electrons

Question 33

covalent bond

Answer 33

Covalent bonds involve a sharing of electrons where as ionic bonds are created by a transfer of electrons.

Question 34

what is an ionic compound

Answer 34

contains ions and has charges, 99% has a metal and a non-metal, keep in mind that amonium is always ionic. more electronegtive element always ends in -ide, e.g., trichloride, oxide, etc.

Question 35

molecular compounds

Answer 35

both non-metals

Question 36

explain the chemical suffixes -ate, and -ite

Answer 36

No2- , -ate, -ite, ate has one more oxygen than ite, if you see ate or ite, its a polyatomic ion that has oxygen.

Question 37

polyatomic atoms (((4444)))

Answer 37

ions composed of many atoms

Question 38

what if atom has more oxygen than ate

Answer 38

put per infront of it, e.g., perchlorate

Question 39

what if you have something with one less oxygen than ite

Answer 39

put hypo in front of it, e.g., hypochlorite

Question 40

what is a compound

Answer 40

a substance comprised of two different elements

Question 41

how do you name anion

Answer 41

suffix -ide

Question 42

hydroxide cyanide chromate chemical formulas

Answer 42

OH- CN- CrO4*2-

Question 43

how to name FeCl2 and FeCl3 (i think this is for transition metals)

Answer 43

iron (II) chloride iron (III) chloride

Question 44

find number of Cu2S

Answer 44

2cu + s = 0 2x + (-2) = 0 (2x)/2 = 2 x = 1

Question 45

ionic compound with transition metals,

Answer 45

dont need to use tetra, tri, mono etc. i think

Question 46

how to name ion with suffix ide

Answer 46

hydro prefix, the ic suffix, then acid

Question 47

how to name ion with suffix ate

Answer 47

ic + acid

Question 48

how to name ion with suffix ite

Answer 48

ous + acid

Question 49

how much is a mole

Answer 49

6.022 x 10*23 purpose of mole is to represent a quantity of atoms particles

Answer 50

nitrogen 14 atomic mass, means 14 grams per mole

Answer 51

calcium phospate Ca*+2PO4*3- = Ca3(PO4)2

Question 52

how many moles of carbon atoms are present in 30g of carbon

Answer 52

30g C / 1 x 1 mol C / 12g C = 2.5 mol C

Question 53

how many atoms are present in 5 moles of zinc

Answer 53

5 mol Zn / 1 x 6.022 x 10^23 / 1 mol Zn = 3.011 x 10^24 atoms Zn

Question 53

how many grams are there in 3.5 mols of carbon atoms

Answer 53

3.5 mol C / 1 x 12g C / 1 mol C = 42 g C

Question 53

how many moles of copper are equilvalent to 8 x 10^24 copper atoms

Answer 53

8 x 10^24 Cu atoms / 1 x 1 mol Cu / 6.022 x 10^23 atoms Cu = 13.28 mol Cu

Question 53

how many molecules of CO2 can be found in 55.1g of CO2?

Answer 53

CO2 -> C + 2(0) -> 12.01 +2(16) 12.01 + 32 44.01 grams per mole (g/mol) 55.1g CO2 / 1 x 1 mol CO2 / 44.01g CO2 x 6.022 x 10^23 CO2 / 1 mol CO2 = 7.54 x 10^23 molecules of CO2

Question 54

rules for writing chemical formulas

Answer 54

1.Each atom present is represented by its element symbol. 2. The number of each type of atom is indicated by a subscript written to the right of the element symbol. 3. When only one atom of a given type is present, the subscript 1 is not written.

Question 55

definition of isotope

Answer 55

Atoms of an element which have the same atomic number, but different atomic masses. i.e. they have a different number of neutrons