General Knowledge
How many valence electrons do elements in Group 18 have?
What is the exception to this rule?
8 valence electrons, with the exception of He, which only has 2 valence electrons due to there only being one electron shell/ring
What is the Law of Conservation of Mass?
Mass cannot be created nor destroyed, only rearranged.
What is Avogradro's number?
6.02x1023 = 1mole
Define Activation Energy.
the minimum energy colliding particles must have in order to react
What can block gamma rays?
Lead and/or LOTS of concrete.
Why does the atomic radius increase with each period, going down the periodic table?
With each period, a new energy shell (or electron ring) is added to the atoms. By gaining more energy shells, the atomic radius is getting bigger.
Balance the following chemical equation:
___ C3H8 + ___ O2 --> ___ CO2 + ___ H2O
1 C3H8 + 5 O2 --> 3 CO2 + 4 H2O
Find the molar mass of C8H10N4O2 (caffeine). Include UNITS in your answer!!!
194 g/mol
What does a catalyst do? How does it achieve that function?
It's a substance that increases the rate of a chemical reaction by lowering the activation energy (Ea)
Why did Marie Curie struggle to get an education?
Because she was poor and a woman (Polish universities were not allowing women to enroll at that time)
Describe each of the following:
Cations and Anions
Cation – a positively charged ion; occurs when an atom loses electron(s); usually metals
Anion – a negatively charged ion; occurs when an atom gains electron(s); usually nonmetals
Balance the following equation:
___ NH3 + ___ O2 --> ___ N2 + ___ H2O
4 NH3 + 3 O2 --> 2 N2 + 6 H2O
Find the molar mass of Al2(CO3)3. Include UNITS in your answer!!!
234 g/mol
Does every collision between reacting particles lead to products? Explain.
No, if they do not have enough kinetic energy (or have too much), then the particles will bounce off each other.
What did Marie Curie discover? There are three things...
Radioactivity, Radium, and Polonium
Where do you find the metalloids on the periodic table? What makes metalloids different?
Along the stair-step line on the periodic table (in the middle)
Metalloids contain BOTH metallic and nonmetal properties.
Identify this type of reaction:
2 H2O2 --> 2 H2O + O2
Decomposition Reaction
How many moles are in 70 grams of H2O? Include your UNITS in your answer!!!
3.89 moles
You are given the following reaction: 22 kJ + N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
What direction does equilibrium shift (Left or Right or No Change) when the system increases the concentration of N2?
Equilibrium will shift right (towards the products)
What's the difference between Fusion and Fission?
Fusion is the process by which multiple small atomic nuclei join together to form a heavier nucleus.
Fission is the process of splitting an atom into smaller pieces.
What is an isotope?
An atom with the same number of protons/ electrons, but differing in the number of NEUTRONS; therefore, differing in their mass as well
(i.e. Carbon-12 and Carbon-14 are isotopes)
Identify this type of reaction:
Fe + Cu(NO3)2 --> Fe(NO3)2 + Cu
How many atoms are in 104 grams of NH3? Include your UNITS in your answer!!!
3.68 x 1024 atoms
You are given the following reaction: 22 kJ + N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
What direction does equilibrium shift (Left or Right or No Change) when the system decreases the temperature?
Equilibrium will shift left (towards the reactants).
You're given the following equation. What is the missing piece AND what kind of radioactive decay is this?
208 84Po → 204 82Pb + ____
4 2He
Alpha Decay