STATES OF MATTER
ATOMS AND ELEMENTS
BONDING
REACTIONS
USING MOLES
100
What is the change from solid to gas called?
sublimation
100
How many electrons can occupy the first electron shell?
2
100
What type of bonding involves transfer of electrons?
ionic
100
What is the formula of magnesium chloride and why?
MgCl₂
Mg is in group 2 (has 2 electrons)
Cl is in group 7 (needs 1 electron)
100
How much is Avogadro’s constant?
6.022 × 10²³
200
The diagram shows a heat curve for H2O. What is happening during the section marked X?
Liquid water getting warmer
200
An atom has 12 protons, 12 electrons and 13 neutrons. What is its mass number?
25 AMU
200
How many electrons are involved in a C=C double covalent bond?
4 electrions
200
Balance:
Fe + O₂ → Fe₂O₃
4Fe + 3O₂ → 2Fe₂O₃
200
How many moles are in 18 g of H₂O?
1 mol
300
he diagram shows a heating curve for substance X. Which process — phase change or the heating of a solid, liquid, or gas — requires the most energy?
boiling (latent heat of vaporistaion)
300
What is the name given to atoms of the same element with different numbers of neutrons?
Isotopes
300
Oxygen has the electron configuration: 2,6
What is the typical charge on an oxide ion?
2-
300
What type of reaction (energetically) is shown in the energy profile diagram?
endothermic
300
What volume does 1 mol of gas occupy at RTP?
24 dm³
400
Hydrogen gas (H₂) and chlorine gas (Cl₂) are released simultaneously from opposite ends of a long tube. They react to form hydrogen chloride (HCl). Where along the tube would the HCl product form, and why?
Z, because H2 is lighter than Cl2
400
An atom of an element has the following electron configuration.
2, 8, 7
Which group and period is the element in?
Answer: Group 17, Period 3
group 7 (17)
period 3
400
Which conducts electricity when molten: NaCl or SiO₂? Why?
NaCl, because its ionic.
400
What is the Mr (relative molecular mass) of CaCO₃?(Ar of Ca is 40)
100
400
How many moles are present in 250 cm³ of a 0.40 mol/dm³ solution?
0.10 mol
0.4 x 0.25 =
4/10 x 1/4 =
4/40 = 1/10
500
The diagram shows a heating curve. What is the correct term for X? 
Latent heat of fusion
500
An element contains 80% isotope X with mass 10 and 20% isotope Y with mass 11. What is its relative atomic mass?
10.2 AMU
(0.8 x 10) + (0.2 x11) = 10.2
500
How many covalent bonds does each carbon atom form in graphite?
3
500
What percentage of CaCO₃ is oxygen by mass?
48%
500
A compound contains 40% carbon, 6.67% hydrogen and 53.33% oxygen. What is its empirical formula?
CH₂O
40/12 = 3.33
6.67/1 = 6.67
53.33/16 = 3.33