Chemistry Flashcards
What is an atom
The smallest unit into which matter can be divided
The building blocks of all matter
What is an atom made up of
Subatomic particles (protons, neutrons, electrons)
What are protons charge?
+1
Positively charged
Where are protons located in an atom
In the nucleus
What charge do neutrons have?
0
No electric charge
Where are neutrons located in an atom
Nucleus
What contributes to the atomic mass of an atom
The protons and neutrons
What is the mass of a proton
1
What is the mass of a neutron
1
What is the mass of an electron
1/1800
Basically 0
What is the charge of electrons
-1
Negatively charged
Where are electrons found in an atom
Outside of the nucleus: in the orbitals/ shells
How many electrons can the first orbital hold?
2
How many electrons can the second orbital hold?
8
How many electrons can the outside orbital hold
8
What is another name for the outside shell?
Valence Shell
What is valency
The ‘bonding power’ of an element
How is valency determined
By the number of outer (valence) electrons
How are elements grouped
By their valency
Outer electrons
What is the octet rule?
The most stable arrangement of electrons is a full outer shell (2 for the first shell and 8 for the others)
What is the atomic mass equation
Number of protons + number of neutrons
What is a catalyst?
A substance that speeds up a chemical reaction without being changed by the reaction.
How does a catalyst speed up the chemical reaction?
Be lowering the activation energy (EA)
What is an exothermic reaction?
A reaction releasing energy (as heat)
What is an endothermic reaction?
A reaction absorbing energy (as heat)
In a reaction coordinate diagram, what does the delta h represent?
The change in energy (enthalpy)
What is radiation?
Particles or waves emitted by radioactive substances
What is a Geiger counter?
A device for measuring radioactivity
What is combustion?
When a substance reacts with oxygen and releases energy
What is a fuel?
Any substance that reacts with oxygen and releases energy
What does universal indicator do
It indicates the pH of substances by changing colour in different concentrations of h+ ions
What is a substances pH?
It’s concentration of H+
What are acids?
Substances that release H+ ions when they dissolve in water
What is a H+ ion?
A hydrogen atom that has lost its electron
What are bases?
Substances that absorb hydrogen ions
What is an alkali?
A base soluble in water
All alkalis are bases, but not all bases are alkalis
What are reactants?
The things that go into a chemical reaction
What are the products?
The things that are made in a chemical reaction
What is the law of Conservation of Mass?
The mass of the products in a chemical reaction must equal the mass of the reactants
What happens to the atomic number and mass number when when an atoms nucleus decays and releases an alpha particle
The mass number decreases by 4
The atomic number decreases by 2
What happens to the atomic number and mass number when when an atoms nucleus decays and releases a beta particle
Mass number stays the same
Atomic number increases by 1
What are 4 uses of radiation?
X-ray,
Microwave
Radio
Chemotherapy
What are the 7 different levels on the electromagnetic spectrum
Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays
Why are alpha particles, beta particles and gamma rays classified as forms of ionising radiation?
Because they have the ability to remove electrons from atoms and molecules
Why are alpha particles the least dangerous radiation?
Cause they are too slow and big to break through things
What will make an atom radioactive?
The nucleus is unstable and so it emits particles or waves to form a more stable atom
What pigment does photosynthesis use to absorb sunlight?
Chlorophyll
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration is respiration with oxygen and anaerobic is without
Which is more effective- aerobic or anaerobic respiration?
Aerobic is 17x more efficient
Metal + acid =
Salt and hydrogen
Acid and alkali =
Salt and water
Acid + metal hydroxide
Salt and water
Acid + metal carbonate
Salt + water + carbon dioxide
What are acids?
Proton donators (release H+ ions)
What are bases?
Proton acceptors (absorb H+ ions)
What is the pH?
Measure of the number of H+ ions in a solution
Do strong acids have a high or low pH?
Strong acids-lower pH
Weak acids- higher pH
What is the valency of each element group?
1|2|3|4|5|6|7|8
1|2|3|4|3|2|1|0
What are ions?
Charged atoms
How are ions formed?
When electrons move from one atom to another
What determines whether an ion is positive or negative?
If an electron leaves then that atom becomes a positive ion (cation)
If an atom gains an electron it becomes a negative anion (anion)
What is an element?
A substance made up of only one type of atom
E.g. hydrogen H
What is a compound?
A substance that is made up of 2 or more different types of atom chemically joined
E.g. water H2O
How do you find out the chemical formula
S- Substance |. Be C
V- Valency |. 2 4
S- Swap |. 4 2
D- Divide |. 2 1
F-formula |. Be2Cl
What is the chemical formula for lithium and boron?
Li3B
What do you call a positive ion
Cation
What do you call a negative ion
Anion
What is the chemical formula for sulphuric acid?
H2SO4
What is the formula for hydrochloric acid
HCI
What is the chemical formula for phosphoric acid
H3PO4
