AY 2425 JC1 atoms, molecule and stoichometry

Multiple Select

read sub chapter 3.1 unified atomic mass unit

which statements below describe "UNIFIED ATOMIC MASS UNIT"

• one twelfth of an unbound neutral atom of the

  carbon-12 isotope in its ground state

• it is called as standard atom to weigh atom

• one twelfth of the mass

  of a carbon-13 atom

• one twelfth of the mass

  of a carbon-12 atom

• the unit is u or Da which equals to 1.66 × 10−27 kg

​since atom is too small, all calculation of mass is considered as relative mass, relatively to unified atomic mass unit, or u.

Match

Match the following

define the following

• relative atomic mass

• relative isotopic mass

• relative molecular mass

• relative formula mass

weighted average mass of an atom in a given sample of element compared to unified atomic mass unit

mass of a particular isotope of an element which has the

Avogadro number of atoms (6.02 × 1023)

ratio of the weighted average mass of a molecule of a covalent

compound to the unified atomic mass

ratio of the weighted average mass of a

compound containing ions to the unified atomic mass

• weighted average mass of an atom in a given sample of element compared to unified atomic mass unit

• mass of a particular isotope of an element which has the

  Avogadro number of atoms (6.02 × 1023)

• ratio of the weighted average mass of a molecule of a covalent

  compound to the unified atomic mass

• ratio of the weighted average mass of a

  compound containing ions to the unified atomic mass

​HYDRATED AND ANHYDROUS COMPOUNDS

​water of crystallization means that some compound contains water in their structure

Match

Match the following

• hydrated compound

• anhydrous compounds

• cobalt(II) chloride-6-water

• CuSO4·5H2O

• anhydrous copper(II) sulfate

compound containing water of crystallization

compound does not contain water of crystallisation

CoCl2·6H2O

copper(II) sulfate-5-water

CuSO4

• compound containing water of crystallization

• compound does not contain water of crystallisation

• CoCl2·6H2O

• copper(II) sulfate-5-water

• CuSO4

Open Ended

Use the Periodic Table to calculate the relative formula masses 1 of the following:

a. calcium chloride, CaCl2

b. copper(II) sulfate, CuSO4

c. ammonium sulfate, (NH4)2SO4

d. magnesium nitrate-6-water, Mg(NO3)2·6H2O

​MASS SPETROMETER

Match

Match the following

• what is the meaning of m/e

• how many different isotopes present?

• which is the most abundant isotopes

• write isotopic symbol for the lightest isotope

ratio of mass/charge

4 isotopes

Sr-88

38Sr-85

• ratio of mass/charge

• 4 isotopes

• Sr-88

• 38Sr-85

Open Ended

calculate the relative atomic mass of strontium

​IDENTIFICATION OF ORGANIC COMPOUND USING MASS SPECTROMETRY

​The main use of mass spectrometry is in the identification of organic compounds. As in other forms of spectroscopy, a substance can be identified by matching its spectrum against the spectra of known substances stored in a database. This technique is known as ‘fingerprinting’.

Open Ended

look at fig 3.10, which shows the mass spectrum of ethanol, C2H5OH. a structural isomer of ethanol is methoxymethane, an ether with the formula of CH3OCH3

predict the mass-to-charge ratio of a fragment that would appear on the mass spectrum of methoxymethane but does not appear on ethanol's mass spectrum

Open Ended

identify the fragments with mass-to-charge ratios of

a. 15

b. 43

c. 45

d. 60

​CHEMICAL FORMULAE AND CHEMICAL EQUATIONS

Match

Match the following

IONIC COMPOUNDS

• calcium ion

• aluminium ion

• iron(II) ion

• rubidium ion

• cobalt(III) ion

Ca2+

Al3+

Fe2+

Rb+

Co3+

• Ca2+

• Al3+

• Fe2+

• Rb+

• Co3+

Match

Match the following

IONIC COMPOUNDS

• bromide ion

• sulfide ion

• chloride ion

• phosphide ion

• oxide ion

Br-

S2-

Cl-

P3-

O2-

• Br-

• S2-

• Cl-

• P3-

• O2-

Match

Match the following

IONIC COMPOUNDS

• ammonium ion

• carbonate ion

• nitrate ion

• phosphate ion

• sulfate ion

NH4 +

CO3 2-

NO3 -

PO4 3-

SO4 2-

• NH4 +

• CO3 2-

• NO3 -

• PO4 3-

• SO4 2-

Match

Match the following

IONIC COMPOUNDS

• ammonium sulfate

• potassium carbonate

• barium nitrate

• sodium phosphate

• lithium sulfide

(NH4)2SO4

K2CO3

Ba(NO3)2

Na3PO4

Li2S

• (NH4)2SO4

• K2CO3

• Ba(NO3)2

• Na3PO4

• Li2S

Multiple Choice

which one is the correct balanced equation of

iron + hydrochloric acid $$\rightarrow$$ iron(II) chloride + hydrogen

• Fe(g) + 2 HCl(aq) $$\rightarrow$$ FeCl2(aq) + H2(g)

• Fe(s) + 2 HCl(aq) $$\rightarrow$$ FeCl2(aq) + H2(g)

• 2 Fe(s) + 6 HCl(aq) $$\rightarrow$$ 2 FeCl3(aq) + 3 H2(g)

• 2 Fe(g) + 6 HCl(aq) $$\rightarrow$$ 2 FeCl3(aq) + 3 H2(g)

Open Ended

write the balanced equation of

aluminium hydroxide breaks down on heating to form aluminum oxide and water

along with their state symbol

Open Ended

write the balanced equation of

hexane burns in excess oxygen to form carbon dioxide and water

along with their state symbol

Match

Match the following

• decomposition of calcium carbonate

• displacement of zinc from reaction aluminum and zinc sulfate

• dehydration of sugar

• neutralization of acid and base

CaCO3(s) = CaO(s) + CO2(g)

2Al(s) + 3ZnSO4(aq) = Al2(SO4)3 + 3Zn

C6H12O6(s) = 6C(s) + 6H2O(g)

2KOH(aq) + H2SO4(aq) = K2SO4(aq) + 2H2O(l)

• CaCO3(s) = CaO(s) + CO2(g)

• 2Al(s) + 3ZnSO4(aq) = Al2(SO4)3 + 3Zn

• C6H12O6(s) = 6C(s) + 6H2O(g)

• 2KOH(aq) + H2SO4(aq) = K2SO4(aq) + 2H2O(l)

Multiple Choice

• A

• B

• C

• D

Open Ended

Change these full equations to ionic equations.

a. H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(I)

b. Br2(aq) + KI(aq) → 2KBr(aq)+I2

Open Ended

Write ionic equations for these precipitation reactions.

a. CuSO4(aq) + 2NaOH(aq) → Cu(OH)2(s) + Na2SO4(aq)

b. Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)